Sách Giáo Khoa Hóa Học 11

" Sách Giáo Khoa Hóa Học 11 🔙 Quay lại trang tải sách pdf ebook Sách Giáo Khoa Hóa Học 11 Ebooks Nhóm Zalo BO GIAO DUC VA OAO TAO NHA XUAT BAN GIAO DUC VIET NAM BO GIAO DUC VA DAO TAO NGUYfiN XUAN TRUONG (Tong Chu bien) Lfi MAU QUYfiN (Chu bien) PHAM VAN HOAN - Lfi CHI KlfiN HOA HOC (Tdi bdn ldn thii ba) il N H A XUAT BAN GIAO DUC VIET NAM Chiu trach nhiem xuat ban : Chu tich HDQT kiem Tdng Giam doc NGO TRAN Al Pho Tong Giam doc l Na+ + Cl" HCl > H+ + Cl NaOH > Na+ + OH" II - PHAN LOAI CAC CHA T DIEN Ll 1. Thi nghiem Chuan bi hai cdc : mgt cdc dung dung dich HCl 0,1 OM, cdc kia dung dung dich CH3COOH 0,1 OM va lap vao bd dung cu nhu hinh 1.1. Khi nd'i cac dau day dSn dien vdi ciing mgt ngudn dien, ta tha'y bdng den d cdc dimg dung dich HCl sang hon so vdi bdng den d cdc dung dung dich CH3COOH. DiSu dd chung td rang : ndng dg ion trong dung dich HCl ldn hon ndng do ion trong dung dich CH3COOH, nghia la sd phan tir HCl phan li ra ion nhi6u hon so vdi sd phan tu CH3COOH phan li ra ion. Dua vao miic do phan li ra ion cua cac chat dien li khae nhau, ngudi ta chia cac chat dien li thanh chat dien li manh va chat dien li ye'u. 2. Chat dien li manh va chat dien !i yeu a) Chdt dien li manh Chat dien li manh la chat khi tan trong nudc'-', cac phan tu hoa tan deu phan li ra ion. ' " Nhiiu chat khi nong chay cung phan li ra ion, nen a trang thai nong chay cac chat nay dan dien diroc. '-' Tat ca cac chat deu it nhieu tan trong nirac. Thi du, a 25°C nong do bao hoa cua BaS04 la 1,0.10-5 ,^oi/]_ cua AgCl la 1,2.10-5 molA, cua CaCOj la 6,9.10-^ mol/1, cua Fe(OH)2 la 5,8.10-6 mol/1. Thi du. NaCl la chat dien li manh. Ne'u trong dung dich cd 100 phan tu NaCl hoa tan. thi ca 100 phan tu deu phan li ra ion. Nhiing chat dien li manh la cac axit manh nhu HCl. HNO3. HCIO4. H2SO4, ... ; cac bazo manh nhu NaOH. KOH. Ba(OH).. CalOH)^.... va hau het cac mud'i. Trong phuong trinh dien li cua chat dien li manh. ngudi ta diing mgt mui ten chi chieu cua qua trinh dien li. Thi du : NHjSO^ > 2Na+ + SO^" Vi sir dien li cua Na^SOj la hoan toan. nen ta d6 dang tfnh dugc ndng do cac ion do NaoSO^ phan li ra. Thf du. trong dung dich Na2S04 0,1 OM. ndng dg ion Na* la 0.20M va ndng dg ion S0^~ laO.IOM. b) Chdt dien li yeu Qiat dien li ye'u la cha't khi tan trong nudc chi cd mgt phan sd phan tti hoa tan phan li ra ion. phan con lai van tdn tai dudi dang phan tii trong dung dich. Thf du. trong dung dich CH3COOH 0.043M. eti 100 phan tu hoa tan cd 2 phan til phan li ra ion. con lai 98 phan ni khdng phan li. Vay. CH3COOH la chat dien li yeu. Nhung cha:t dien li yeu la cac axit ye'u nhu CH3COOH. HQO. H.S. HF. H2SO3. ... : cac bazo yeu nhu Bi(OH).. MglOH)^. ... Trong phuong trinh dien li ciia chat dien li ye'u. ngudi ta diing hai mui ten ngugc chi6u nhau. Thi du : CH3COOH ^ ^ CHjCOO" + H+ Su phan li ciia chat dien li yeu la qua trinh thuan nghich. khi nao tdc do phan li va tdc do ket hgp cac ion tao lai phan tir bang nhau. can bang ciia qua trinh dien li dugc thiet lap. Cdn bdng dien li la cdn bdng dgng. Gid'ng nhu mgi can bang hoa hgc khae. can bang dien li ciing tuan theo nguyen If chuydn dich can bang Lo Sa-to-li-e. BAI TAP 1- Cac dung dich axit nhu" HCl, bazo nhif NaOH va muoi nhu' NaCl dan dien dvsac, con cac dung dich nhu' ancol etylic, saccaroza, glixerol khong dan dien la do nguyen nhan gi ? 2. Sir dien li, chat dien li la gi ? NhCrng loai chat nao la chat dien li ? The nao la chat dien li manh, chat dien li ye'u ? Lay thf du va viet phuong trinh dien li cua chung. 3. Viet phu'ong trinh dien li cua nhCrng chat sau : a) Cac chat dien li manh : Ba(N03)2 0,10M ; HNO3 0,020M ; KOH 0,010M. Tinh nong dp moi cua tCrng ion trong cac dung djch tren. b) Cac chat dien li yeu : HCIO, HNOj. 4. Chon cau tra ldi dung trong cac cau sau day : Dung dich chat dien li dan dien dirge la do A. sg chuyen dich cua cac electron. B. sir chuyen dich cua cac cation. C. su chuyen dich cua cac phan tir hoa tan. D. sU chuyen djch cua ca cation va anion. 5. Chat nao sau day kfiong dan dien dugc ? A. KCl ran, khan. B. CaClj nong chay. C. NaOH ndng chay. D. HBr hoa tan trong nudc. Bdi W 2 r I - AXIT 1. Ojnh nghia AXIT, BAZO VA MUOI & Bie't the nao la axit, baza, hidroxit luang tfnh, muoi theo thuye't A-re-ni-ut va viet dugc phuang trinh dien li cua chung Theo thuye't A-re-ni-ut, axit la chat khi tan trong nudc phan li ra cation H"''. Thi du : HCl > H+ + Cl" CH3COOH ;^ ^ H+ + CH3COO Cac dung dich axit d6u cd mdt sd tinh cha't chung, dd la tinh cha't ciia cac cation H"'" trong dung dich. 2. Axit nhieu naic Tir hai thi du tren ta thay, phan tu HCl ciing nhu phan tir CH3COOH trong dung dich nudc chi phan li mgt nac ra ion H+. Dd la cac axit mgt ndc. Nhiing axit khi tan trong nudc ma phan tu phan li nhi6u nac ra ion H+ la cac axit nhieu ndc. Thidu : H3PO4 HTPO^ HFO^ ^— <— =± H+ + H2PO4 H"*" + HPO? H++ PO^" Phan tu H3PO4 phan li ba nac ra ion H+, H3PO4 la axit ba ndc. II - BAZO Theo thuyet A-re-ni-ut, bazo la chat khi tan trong nudc phan li ra anion OH". Tin du : NaOH > Na+ + OH" Cac dung dich bazo deu cd mdt sd tfnh chat chung, dd la tfnh cha't cua cac anion OH trong dung dich. III - HIDROXIT LUONG TINH Hidroxit ludng tfnh la hidroxit khi tan trong nudc vua cd the phan li nhu axit vtra cd the phan li nhu bazo. Thf du, Zn(OH)2 la hidroxit ludng tinh : Su phan li theo kieu bazo : Zn(0H)2 <= ^ Zn^^ -i- 20H Sir phan li theo kieu axit: Zn(0H)2 •^=^ ZnOj" ^^^ + 2H+ De the hien tfnh axit cua Zn(OH)2, ngudi ta thudng vie't nd dudi dang HoZnOj. Cac hidroxit ludng tfnh thudng gap la Zn(0H)2, A1(0H)3, Sn(OH)2, Pb(0H)2. Chting d6u ft tan trong nudc va luc axit (kha nang phan li ra ion), lire bazo deu ye'u. IV - MUOI 1. Ojnh nghla Mudi la hgp chat khi tan trong nudc phan li ra cation kim loai (hoac cation NH4 ) va anion gdc axit. Thi du : (NH4)2S04 > 2NH ; + SO^" NaHC03 > Na++ HCO3 Mud'i ma anion gd'c axit khdng cdn hidro cd kha nang phan li ra ion H+ (hidro cd tinh axit)(2) dugc ggi la mudi trung hod. Thi du : NaCl, (NH4)2S04, Na2C03. Neu anion gdc axit cua mudi van cdn hidro cd kha nang phan li ra ion H+ thi mud'i dd dugc ggi la mudi axit. Thi du : NaHCOj, NaH2P04, NaHS04. ('' Thuc te, trong dung dich ton tai ion [Zn(OH)4]2 : Zn(OH), + 2H2O < > [Zn(OH) J' - + 2H* f2) Trong goc axit cua mot so muoi nhu Na2HP03, NaHjPOj vdn con hidro, nhimg cac muoi do la muoi trung hoa, vi cac hidro do khong co tfnh axit. 2. Su dien li cua mudi trong nuae HSu het cac mudi khi tan trong nudc phan li hoan toan ra cation kim loai (hoac cation NH4) va anion gdc axit (trir mdt sd mud'i nhu HgClj, Hg(CN)2 ... la cac chat dien li ye'u). Thi du : K2SO4 > 2K+ + SO^" NaHSOj > Na+ + HSO3 Neu anion gd'c axit cdn hidro cd tfnh axit, thi gd'c nay tiep tuc phan li yeu ra ion H+. Thi du : HSO3 ^ ^ H+ + SO^" BAI TAP 1- Phat bieu cac djnh nghla axit, axit mot nac va nhieu nac, bazo, hidroxit IUdng tfnh, mudi trung hoa, muoi axit. Lay cac thi du minh hoa va viet phuong trinh dien li cua chung. 2. Viet phuong trinh dien li cua cac chat sau : a) cac axit yeu : H2S, H2CO3. c) cac mudi : K2CO3, NaCIO, NaHS. b) bazo manh : LiOH. d) hidroxit IUdng tfnh : Sn(0H)2. 3. Theo thuye't A-re-ni-ut, ke't luan nao sau day la dung ? A. Mot hgp chat trong thanh phan phan tii c6 hidro la axit. B. Mpt hop chat trong thanh phan phan tCr c6 nhdm OH la bazo. C. Mot hgp chat c6 kha nang phan li ra cation H"^ trong nU6c la axit. D. Mgt bazd khong nhat thiet phai c6 nhom OH trong thanh phan phan tCr. 4. Ddi vdi dung djch axit ye'u CH3COOH 0,10M, neu bo qua sUdien li cua nUdc thi danh gia nao ve nong do moi ion sau day la dung ? A. [H+] = 0,10M C. [H+] > [CH3COO-] B. [HT < [CH3COO-] D. [HT<0,10M 5. odi vdi dung dich axit manh HNO3 0,10M, ne'u bo qua sudien li cua nudc thi danh gia nao ve nong dp moi ion sau day la dung ? A. [H+] = 0,10M C. [HT> [NO3] B. [HT < [NO3] D. [HT < 0,10M 10 SUOIEN Ll CUA NUOC pH. CHAT CHi THS AXIT-BAZO & Biei danh gia dp axit va do ki^m cua cac dung dich theo nong dp ion H+ va pH. & Biei mau cua mpt so chai chi thi trong dung dich a cac khoang pH khae nhau. I - NUOC LA CHAT OIEN Ll RAT YEU 1. Sir dien li cua nuoc Bang dung cu do nhay, ngudi ta tha'y nudc ciing dSn dien nhung cue ki ye'u. Nudc dien li ra't ye'u : H2O ^ ^ H+ + OH- (1) Thuc nghiem da xac dinh dugc rang, d nhiet do thudng cii 555 trieu phan tir H2O chi cd mgt phan tii phan li ra ion. 2. Tich sd ion ciia nudc Tii phuong trinh dien li ciia H2O (1), ta thay mdt phan tii H2O phan li ra mgt ion H"*" va mdt ion OH", nghTa la trong nudc ndng do H"*" bang ndng dg OH". Nudc cd mdi trudng trung tinh, nen cd the dinh nghia : Mdi trudng trung tfnh la mdi trudng trong dd [H+J - [OH^j. Bang thuc nghiem, ngudi ta da xac dinh dugc ndng do ciia chiing nhu sau : [H+] = [0H-] = 1,0.10-7 (mol/1) d 250C Dat K„ o (2500 = [H+].[OH-] = 1,0.10"^ x 1,0.10"^ = 1,0.10-'^ Tfch sd K H^O H^ OH dugc ggi la tfch sd ion cua nudc. Tfch sd nay la hang sd d nhiet do xac dinh, tuy nhien gia tri tich sd ion cua nudc la 1,0.10^'"* thudng dugc dung trong cac phep tfnh, khi nhiet dg khdng khae nhieu vdi 25"C. 11 Mdt each gan dung, cd the coi gia tri tich sd ion cua nudc la hang sd ca trong dung dich loang cua cac chai khae nhau. 3. Y nghia tich sd ion cua nudc a) Moi truang axit Khi hoa tan axit vao nudc, ndng do H+ tang, vi vay ndng do OH" phai giam sao cho tfch sd ion cua nudc khdng ddi. Thf du, hoa tan axit HCl vao nudc de' ndng do H+ bang 1,0.10-3M, thi ndng dg OH" la : 1,0.10"'" [0H-] = r = l,0.10->iM 1,0.10"-^ Vay moi trudng axit la mdi trudng trong dd : [H+]>[OH-] hay [H+] > 1.0.10'^M b) Moi tru&ng kiem Khi hoa tan bazo vao nudc, ndng do OH" tang, vi vay ndng do H"*" phai giam sao cho tfch sd ion cua nudc khdng ddi. Thf du, hoa tan bazo vao nudc de ndng do OH- bang 1,0.10'^M thi ndng do H+ la : [H.]= 1:^^:1 ^ = 1,0.10-'^M 1,0.10"^ Vay moi trudng kiem la moi tnrdng trong dd : [H+] < [0H-] hay [H^] < 1,0.10-^M Nhiing thf du tren cho thay, ne'u biet ndng do H+ trong dung dich nudc thi ndng do OH- cung dugc xac dinh va ngugc lai. Vi vay, dg axit va dg kiem cua dung dich cd the dugc danh gia chi bang ndng do H"'": Mdi trudng trung tinh : [H+] = I.O.IO-^M. Mdi trudng axit: [H+] > 1,0.10-^M. Mdi trudng kiem : [H+] < 1,0.10'^M. 12 II - KHAI NIEM v i pH. CHAT CHJ THj AXIT - BAZO 1. Khai niem ve pH Nhu da thay d tren, cd the danh gia do axit va dg kiem cua dung dich bang ndng dg H+. Nhung dung dich thudng dung cd ndng do H+ nhd. De tranh ghi ndng dg H+ vdi sd mii am, ngudi ta dung gia tri pH vdi quy udc nhu sau : [H+] = 10-P"<'> M. Neu [H+] = lO-^M thi pH = a Thi du : [H+] = 1,0.1 0-2M =^ pH = 2,00 : mdi trudng axit [H+] = 1,0.10-7M r* pH = 7,00 : mdi tnrdng trung tfnh. [H+] = 1,0.10-'°M ^ pH = 10,00 : mdi tnrdng kiem. Thang pH thudng dung cd gia tri tii 1 den 14. Gia tri pH cd y nghia to ldn trong thuc te. Chang han, pH ciia mau ngudi va ddng vat cd gia tri gSn nhu khdng ddi. Thuc vat chi cd the sinh trudng binh thudng khi gia tri pH cua dung dich trong dat d trong khoang xac dinh dac trung cho mdi loai cay. Tdc do an mdn kim loai trong nudc tu nhien phu thudc rai nhieu vao gia tri pH ciia nudc ma kim loai tiep xiic. 2. Chait chi thj axit - bazo Chat chi thi axit - bazo la cha't cd mau bie'n doi phu thudc vao gia tri pH ciia dung dich. Thf du, mau ciia hai chai chi thi axit - bazo la quy va phenolphtalein trong dung dich d cac khoang pH khae nhau dugc dua ra trong bang 1.1. Bang 1.1. Mdu cua quy vd phenolphtalein trong dung dich a cdc khodng pH khdc nhau 7,0 . 1 1 Quy do tim xanh pH < 6 pH > 8 Phenolphtalein ('> v e mat toan hoc pH = -lg[H+]. (^' Trong xut dac, mau hdng hi mat. 13 pH <8,3 khong mau pH > 8,3 hong'^' Trdn lin mgt sd chai chi thi cd mau bien ddi ke tiep nhau theo gia tri pH, ta dugc hdn hgp clid't chi thi van ndng. Dung bang giay tam dung dich hdn hgp nay cd the xac dinh dugc gan diing gia tri pH ciia dung dich (hinh 1.2). [H+] 10"' 10^2 10-3 10 ^ 10-5 10-6 10-^ 10-« 10-^ 10-1° .,0-12 10-'' ' M pH 1 2 3 4 5 6 7 8 9 10 12 14 < 1 • (56 axit tang Irung tinh do kiem tang Hinh 1.2. Mdu cua chd't chi thi vgn ndng (thudc thu MERCK cua Due} a cdc gid tri pH klidc nhau De xac dinh tuong ddi chfnh xac gia tri pH ciia dung dich, ngudi ta diing may dopH. BAI TAP 1. Tich sd ion cua nudc la gi va bang bao nhieu d 25°C ? 2. Phat bieu cac dinh nghTa moi trudng axit, trung tfnh va kiem theo ndng dp H"^ va pH. 3. Chai chi thi axit - bazo la gi ? Hay cho biei mau cCia quy va phenolphtalein trong dung dich d cac khoang pH khae nhau. 4. Mpt dung dich co [OH"] = 1 .S.IQ-^M. Moi trUdng cua dung dich nay la A. axit B. trung tinh C. kiem D. khong xac dinh dUdc 5. Tinh nong dp H"", OH- va pH cua dung dich HCl 0,10M va dung djch NaOH 0,010M. 6. Trong dung dich HCl 0,01 OM, ti'ch sd ion ciia nu6c la A. [H-^] [0H-]> 1,0.10-14 C. [HT [0H-] < 1,0.10-14 B. [H*] [0H-] = 1,0.10-14 D. khong xac djnh dupc. 14 Ttf He 11 GIA TR! pH CUA MOT SO DjCH LONG THONG THl/ONG pH Dich da day Nudc chanh Giam Nudc nho Nudc cam Nudc tieu Nudc de ngoai khong khi Nudc bot Sufa Mau Nudc mat 1,0-2,0 -2,4 3,0 -3,2 -3,5 4,8-7,5 5,5 6,4-6,9 6.5 7,30 - 7,45 7,4 15 PHAN UNG TRAO DOI ION TRONG DUNG DICH CAC CHAT OIEN Ll & Hieu ban chai, dieu kien xay ra phan ung trao doi ion trong dung dich cac chai dien li va viei dugc phuang trinh ion rut gpn cua phan ung. DIEU KIEN XAY RA PHAN UNG TRAO DOI ION TRONG DUNG DICH CAC CHAT DIEN Ll Phan ung tao thanh chat ket tua Thi nghiem. Nhd dung dich natri sunfat (Na2S04) vao d'ng nghiem dung dung dich bari clorua (BaClj) thay ket tua trang cua BaS04 xuai hien : Na2S04 + BaClj BaS d -I- 2NaCl (1) Gidi thich. NajSO^ va BaCl2 deu de tan va phan li manh trong nudc : Na2S04 BaClo 2Na+ -1- soi -> Ba2+ + 2C1- Trong sd bd'n ion dugc phan li ra chi cd cac ion Ba^^ va SO4 kei hgp dugc vdi nhau tao thanh chai ket tua la BaS04 (hinh 1.3), nen thuc chai phan iing trong dung dich la : Ba2+ + SO BaS04 i (2) Hmh 1.3. Chdt ke't tiia BaSO^ 16 Phuang trinh (2) dugc ggi Va phucmg trinh ion nit ggn cua phan img (1). Phuang trinh ion nit ggn cho biet ban chat cua phan iing trong dung dich cac chai dien li. Cach chuydn phuang trinh dudi dang phan tu thanh phuang trinh ion nit ggn nhu sau : - Chuyen tai ca cae chai viia de tan, vira dien li manh thanh ion, cac chai khf, kei tua, dien li yeu de' nguyen dudi dang phan tir. Phuang tnnh thu dugc ggi la phuang trtnh ion day dii, thi du, ddi vdi phan iing (1) ta cd : 2Na+ -1- SO4" + Ba2+ + 20 " -> BaS04i -i-2Na+ -f 2C1- - Lugc bd nhiing ion khdng tham gia phan ung, ta dugc phuang tnnh ion nit ggn Ba2+ + SO^ -> BaS04i TCr phuang trinh nay ta thay rang, mud'n dieu che' kei tua BaS04, can trdn hai dung dich, mdt dung dich chua ion Ba^*, dung dich kia chiia ion SO4". 2. Phan iing tao thanh chait dien li yeu a) Phdn iing tao thdnh nudc Thi nghiem. Nhd vai gigt dung dich phenolphtalein vao cdc dung dung dich NaOH 0,1 OM, dung dich cd mau hdng (hinh 1.4). Rdt tii tii dung dich HCl 0,1 OM vao cdc tren, vira rdt viia khua'y, cho den khi mai mau. Phan ilng nhu sau : HCl -I- NaOH NaCl -I- H2O Gidi thich. NaOH va HCl deu de tan va phan li manh trong nudc : NaOH HCl Na+ + OH H+ + Cl Hmh 1.4. Mdu cua phenolphtalein trong moi trifdng kiem Cac ion OH trong dung dich lam cho phenolphtalein chuyen sang mau hdng. Khi cho dung dich HCl vao, cac ion H+ cua HCl se phan timg vdi cac ion OH cua NaOH tao thanh chai dien li rat yeu la H2O. Phuang trinh ion nit ggn : H+ + OH^ H2O 2 - HH11(C)-A 17 Khi mau ciia dung dich trong cdc mai, dd la liic cac ion H+ cua HCl da phan ling hei vdi cac ion OH- cua NaOH. Phan ling giira dung dich axit va hidroxit cd tinh baza rat de xay ra vi tao thanh chai dien li rai yeu la H2O. Chang han, Mg(0H)2 it tan trong nudc, nhung de dang tan trong dung dich axit manh : Mg(0H)2 (r) + 2H+ > Mg2+ + 2H2O b) Phdn itng tao thdnh axit yeu Thi nghiem. Nhd dung dich HCl vao dng nghiem dung dung dich CH3COONa, axit yeu CH3COOH se tao thanh : HCl -i-CHjCOONa > CH3COOH + NaCl Gidi thich. HCl va CH3C00Na la cac chai de tan va phan li manh : HCl > H+ + C\- CH3C00Na > Na+ + CH3COO Trong dung dich, cac ion H+ se kei hgp vdi cac ion CH3COO- tao thanh chai dien li yeu la CH3COOH (miii giam). Phuong trinh ion nit ggn : H+ + CH3COO- > CH3COOH 3. Phan ung tao thanh chat khi Thi nghiem. Rdt dung dich HCl vao cdc dung dung dich Na2C03 ta thay cd bgt khf thoat ra : 2HC1 + Na2C03 > 2NaCl + CO2 t -1- H2O Gidi thich. HCl va Na2C03 deu de tan va phan li manh : HCl > H+ + C1- Na2C03 > 2Na++ CO^" Cac ion H+ va CO3" trong dung dich kei hgp vdi nhau tao thanh axit yeu la H2CO3, axit nay khdng ben bi phan huy ra CO2 va H2O. 18 2 - HH11(C)-B H+ + CO^ HCO^ H+ + HCO3 H2CO3 Phuang trtnh ion nit ggn : 2H+ + COj" -^ H2CO3 -> CO2 t + H2O -> CO21 + H2O Phan ling giira mudi cacbonat va dung dich axit rat de xay ra vi vira tao thanh chai dien li rat yeu la H^O, viia tao ra chai khi CO2 tach khdi mdi trudng phan ling. Chang han, cac mudi cacbonat it tan trong nudc nhung tan de dang trong cac dung dich axit. Thi du, da vdi (CaC03) tan rat de trong dung dich HCl (hinh 1.5): CaC03 (r) + 2H+ Ca2+ + CO2 t + H2O Da voi Hinh 1.5. Phdn ung tao thdnh chdt khi CO, II - KET LUAN 1. Phan ling xay ra trong dung dich cac chai dien li la phan ung giira cac ion. 2. Phan umg trao ddi ion trong dung dich cac chai dien li chi xay ra khi cac ion kei hgp dugc vdi nhau tao thanh ft nhat mgt trong cac chai sau : - chd't ket tua. - chci't dien li yeu. - chat Jdii. 19 BAI TAP 1. Dieu kien de xay ra phan ung trao ddi ion trong dung djch cac chai dien li la gi ? Lay cac thi du minh hoa. 2. Tai sao cac phan dng giUa dung dich axit va hidroxit cd tfnh bazd va phan Ung giura mudi cacbonat va dung dich axit rai de xay ra ? 3. Lay mdt sd thf du chung minh rang : ban chai cua phan Crng trong dung dich cac chai dien li la phan dng giUa cac ion. 4. PhUdng trinh ion rut gpn cua phan ung cho biet: A. Nhung ion nao tdn tai trong dung djch. B. Nong dp nhung ion nao trong dung djch Idn nhai. C. Ban chai cua phan iTng trong dung djch cac chai dien li. D. Khong tdn tai phan tCr trong dung djch cac chai dien li. 5. Viet cac phuong trinh phan tir va ion rut gpn cua cac phan Ung (ne'u c6) xay ra trong dung djch giuTa cac cap chai sau : d) MgClj + KNO3 e) FeS (r) + HCl g) HCIO + KOH Hiiih 1.6 Chd't ket tua Fe(OH)^ 20 a) Fe2(S04)3 + NaOH b) NH4CI + AgNOj c) NaF + HCl Phan Ung nao dUdi day xay ra trong dung djch tao dupc kei tua Fe(0H)3 (hinh 1.6) ? A. FeS04 + KMn04 + H2SO4 B. Fe2(S04)3 + Kl C. Fe(N03)3 + Fe D. Fe(N03)3 + KOH Lay thf du va viei cac phuong trinh hoa hoc dudi dang phan tCr va ion rut gpn cho cac phan Ung sau : a) Tao thanh chai ket tua. b) Tao thanh chai dien li yeu. c) Tao thanh chai khi. Bdi W 5 r LUYEN TAP AXIT, BAZa VA MUOI. PHAN UNG TRAO DOI ION TRONG DUNG DjCH CAC CHAT DIEN Ll & Cung cd cac kien thiic ve axit, baza va dieu kien xay ra phan ung trao doi ion trong dung dich cac chai dien li. & Ren luyen kT nang viei phuang trinh ion rut gpn cua cac phan ung. I - KIEN THUC CAN NA M VUNG 1. Axit khi tan trong nirdc phan li ra ion H+. 2. Bazo khi tan trong nudc phan li ra ion 0H-. 3. Hidroxit ludng tfnh khi tan trong nudc viTa cd the phan li nhu axit viia cd the phan li nhu baza. 4. Hau hei cac mudi khi tan trong nudc phan li hoan toan ra cation kim loai (hoac cation NH^ ) va anion gd'c axit. Neu gd'c axit cdn chiia hidro cd tfnh axit, thi gd'c dd tie'p tuc phan li yeu ra cation H"*" va anion gd'c axit. 5. Tich sd ion ciia nudc la K^^ ^ = [H+].[OH-] = 1,0.10-14 (d 25 °C). Mgt each gan diing, cd the coi gia tri ciia tfch sd nay la hang sd ca trong dung dich loang cua cac chai khae nhau. 6. Cac gia tri [H"*"] va pH dac trung cho cac mdi tnrdng : Mdi trudng trung tinh : [H+] = 1,0.10-^M hoac pH = 7,00. Mdi trudng axit : [H+] > 1,0.10-^M hoac pH < 7,00. Mdi trudng kiem : [H+] < 1,0.10-7M hoac pH > 7,00. 21 7. Mau cua quy, phenolphtalein va chai chi thi van nang trong dung dich d cac gia tri pH khae nhau (xem bang 1.1 va hinh 1.2). 8. Phan iing trao ddi ion trong dung dich cac chai dien li chi xay ra khi cac ion ket hgp dugc vdi nhau tao thanh it nhai mgt trong cac chai sau : - chd't ke't tiia. - chdt dien li ye'u. - chdt khi. 9. Phuang trtnh ion nit ggn cho biet ban chai cua phan iing trong dung dich cac chai dien li. Trong phuang trinh ion nit ggn, ngudi ta loai bd nhumg ion khdng tham gia phan irng, cdn nhfing chai ket tiia, dien li yeu, chai khi dugc giir nguyen dudi dang phan tii. II - BAI TAP 1. Viei phuong trinh dien li cua cac chai sau : KgS, Na2HP04, NaH2P04, Pb(OH)2, HBrO, HF, HCIO4. 2. Mpt dung dich cd [H''] = 0,01 OM. Tinh [OH"] va pH cua dung djch. Moi trUdng cua dung dich nay la axit, trung tinh hay kiem ? Hay cho biet mau cua quy tim trong dung djch nay. 3. Mpt dung djch co pH = 9,0. Tfnh ndng dp moi cua cac ion H+ va OH- trong dung djch. Hay cho biei mau cua phenolphtalein trong dung djch nay. 4. Viei cac phuong trinh phan tCr va ion rut gpn cua cac phan dng (neu cd) xay ra trong dung djch gida cac cap chai sau : a) Na2C03 + Ca(N03)2 b) FeS04 + NaOH (loang) c) NaHCOg + HCl d) NaHCOg + NaOH e) K2CO3 + NaCl g) Pb(0H)2 (r) + HNO3 h) Pb(0H)2 (r) + NaOH i) CUSO4 + Na2S 22 Phan Ung trao ddi ion trong dung djch cac chai dien li chi xay ra khi A. cac chai phan Ung phai la nhUng chai d i tan. B. cac chai phan Ung phai la nhung chai dien li manh. C. mpt sd ion trong dung djch kei hop dugc vdi nhau lam giam nong dp ion cua chung. D. phan Ung khong phai la thuan nghjch. Ket tua CdS (hinh 1.7a) dupc tao thanh trong dung djch bang cap chai nao dudi day ? A. CdCl2 + NaOH B. Cd(N03)2 + H2S C. Cd(N03)2 + HCl D. CdCl2 + Na2S04 Viei phUdng trinh hoa hoc (dudi dang phan tCr va ion rut gpn) cua phan dng trao ddi ion trong dung djch tao thanh tUng ket tua sau : Cr(0H)3 ; AI(0H)3 ; Ni(0H)2 (hinh 1.7 b, c, d). CdS Cr(0H)3 AI(0H)3 NI(0H)2 a) b) c) d) Hinh 1.7 23 BAI THUC HANH 1 TINH AXIT - BAZO. PHAN UNG TRAO DOI ION TRONG DUNG DjCH CAC CHAT DIEN Ll & Cung cd cac kie'n thiic ve axit - baza va ve dieu kien xay ra phan ung trao doi ion trong dung djch cac chai dien li. & Ren luyen ki nang thuc hanh thf nghiem trong dng nghiem va vdi lugng nho hoa chai. I - NO I DUN G TH I NGHIEM VA CACH TIEN HANH Thi nghiem 1. Tinh axit - bazo a) Dat mdt miu giay chi thi pH len mat kinh ddng hd. Nhd len mau giay dd mot gigt dung dich HCl 0,1 OM. So sanh mau cua mau gia'y vdi mSu chuan de biei gia tri pH. b) Lam tuong tu nhu tren, nhung thay dung dich HCl lan lugt bang tiing dung dich sau : CH3COOH 0,10M ; NaOH 0,10M ; NH3 0,1 OM. Giai thich. Thi nghiem 2. Phan umg trao ddi ion trong dung djch cac chait dien li a) Cho khoang 2 ml dung dich Na2C03 dac vao d'ng nghiem dumg khoang 2 ml dung dich CaClj dac. Nhan xet hien tugng xay ra. b) Hoa tan ket tiia thu dugc d thi nghiem a) bang dung dich HCl loang. Nhan xet cac hien tugng xay ra. c) Mgt dng nghiem dung khoang 2 ml dung dich NaOH loang. Nhd vao dd vai gigt dung dich phenolphtalein. Nhan xet mau ciia dung dich. Nhd tir tii dung dich HCl loang vao d'ng nghiem tren, viia nhd vira lac cho den khi mai mau. Giai thich hien tugng xay ra. Hay viei phuang trinh hoa hgc cua cac phan umg xay ra trong cac thi nghiem tren dudi dang phan tu va dang ion nit ggn. II - VIET TUONG TRINH 24 BAI DOC THEM DO DIEN Ll VA HAN G SO PHAN Ll I -DO DIEN Ll De danh gia miic dg phan li ra ion cua chai dien li trong dung djch, ngudi ta diing khai niem do dien li a. Do dien li a (anpha) ciia chai dien li la ti sd giCra sd phan tii phan li ra ion (n) va tdng sd phan tii' hoa tan (n^) : n a = — Thi du, do dien li cua CH3COOH trong dung dich ndng do 0,043 mol/1 la 0,020 hay 2,0%, nghia la trong dung dich nay cd 100 phan tu CH3COOH hoa tan cd 2 phan tu phan li ra ion, cdn lai 98 phan tii khdng phan li ra ion : a = A . 0.020 Nhu vay, theo dinh nghia ve do dien li thi chat dien li manh cd a = 1, chat dien li yeu cd 0 < a < 1. Chai cd a = 0 la chai khdng dien li. Khi pha loang dung dich thi dd dien li cua cac chai dien li deu tang. Thf du : d 25°C, dg dien li cua CH3COOH trong dung dich 0,10M la 1,3%, trong dung dich 0,0lOM la 4,1%. II - HANG SO PHAN Ll Su phan li cda chat dien li yeu trong dung dich la qua trinh thuan nghich. Khi nao tdc do phan li va td'c do ket hgp cac ion tao lai phan tii bang nhau, can bang cua qua trinh dien li duge thiet lap. Gid'ng nhu mgi can bang hoa hgc khae, can bang dien li cung cd hang sd can bang. Thi du, CH3COOH la axit yeu, trong dung dich cd can bang sau : CH3COOH ^= ^ CH3COO- + H+ 25 6 trang thai can bang, ndng do CH3COOH va ndng do cac ion CH3COO , H+ khdng bie'n ddi nen ta cd : [CH.COQ-JiH^] ICH.COOHl ~ " ^ " 6 day [CH3COOH], [CH3COO-] va [H+] la nong do moi ciia CH3COOH, CH3COO- va H+ d trang thai can bang. Hang sd can bang K, trong trudmg hgp nay dugc ggi la hdng so phdn li axit K^. Gia til cua hang so iv^ chi pisu umgc vao ban chai axit va nhiet do. Gia tri K^ ciia axit cang nhd, luc axit cua nd cang yeu. Thf du : d 25°C, K^ ciia CH3COOH la 1,75.10-5 va cua HCIO la 5,0.10-^. Vay luc axit cua HCIO yeu han so vdi luc axit cua CH3COOH, nghia la neu hai axit nay cd cdng ndng dd moi va d cimg nhiet do thi ndng do moi ciia H+ trong dung dich HCIO nhd hon. Baza yeu cung cd hang sd phan li baza Kj,. Gi;i Iri cua hang so K;^ ciing ch; phu thugc vao ban chai baza va nhiet do. 26 Chuong 2 JCTlty - PHOTPHO & Vi tri cua nito, photpho trong bdng tudn hodn co lien quan nhu the ndo vai cd'u ttio nguyin tu vd phdn tu cm chiing ? £D Cdc dem chd't vd hap chd't ciia nita, photpho co nhvtng tinh chat cabdn ndo ? Gidi thich nhung tinh chd't do dm trin casali thuydt da hoc nhu tMndo ? & Ldm tMndo diiu chi duoc nita, photpho vd mot so hap chat quan trong cm chiing ? Nha may phan dam Phu My 27 ^ ^ NITO Bdi m • & Viet dupc cau hinh electron cua nguyen tunitava cau tao phan tu cua no. & Biei cac tinh chai vat If, hoa hoc, ung dung va dieu che nito. I - V! TRI VA CAU HlNH ELECTRON NGUYEN TU Nita d g thli 7, nhdm VA, chu ki 2 cua bang tuIn hoan. Ca'u hinh electron nguyen tir cua nita la 1 s- 2^- 2p-^ Ba electron d phan ldp 2p cd the tao dugc ba lien ket cdng hoa tri vdi cac nguyen tir khae. Phan tu nita gdm hai nguyen tii, giiia chiing hinh thanh mdt lien kei ba. Cdng thiic ca'u tao ciia phan tii nito la N = N II - TINH CHAT VAT Li O dieu kien thudng, nita la chai khf khdng mau, khdng mui, khdng vi, hai nhe hon khdng khf, hoa long d -196 °C. Khf nita tan rat it trong nudc (d dieu kien thudng, 1 lit nudc hoa tan dugc 0,015 lit khf nito). Nita khdng duy tri su chay va su hd ha'p. III - TINH CHAT HOA HOC Lien kei ba trong phan tu nita rat ben, d 3000 °C nd van chua bi phan huy rd ret thanh cac nguyen tu. 6 nhiet do thudng, nita kha tro ve mat hoa hgc, nhung d nhiet do cao nita trd nen hoat dgng han va cd the tac dung dugc vdi nhieu chat. Trong cac hgp chai cdng hoa tri ciia nita vdi nhumg nguyen td cd dg am dien nhd hom (nhu hidro, kim loai,...), nguyen td nita cd sd oxi hoa - 3. Cdn trong cac hgp chai cgng hoa tri cua nita vdi nhiing nguyen td cd do am dien ldn han (oxi, clo, flo), nguyen td nito cd sd oxi hoa duang, cd the tir -i-l den -i-5. Khi tham gia phan iing oxi hoa - khu, sd oxi hoa ciia nita cd the' giam hoac tang, do dd nd the' hien tinh oxi hoa hoac tinh khir. Tuy nhien, tinh oxi hoa vin la tinh chat chu yeu ciia nita. 28 1. Tinh oxi hoa a) Tdc dung vdi kim loai 6 nhiet do cao, nito tac dung dugc vdi mdt sd kim loai hoat ddng nhU Ca, Mg, Al,... tao thanh nitrua kim loai. Thi dii : 0 ,0 - 3 3Mg + N2 —^^Mg3N 2 magie nitrua b) Tdc dung vdi hidro 6 nhiet do cao, ap suai cao va cd mat chat xiic tac, nita tac dung true tiep vdi hidro, tao ra khi amoniac. t . p -3 N2 + 3H2 < > 2NH3 Trong nhiing phan umg neu tren, sd oxi hoa ciia nguyen td nita giam tii 0 de'n -3 , nita the hien tinh oxi hoa 2. Tinh khu 6 nhiet do khoang 3000 °C (hoac nhiet do cua Id hd quang dien), nita kdt hgp trirc tie'p vdi oxi, tao ra khi nito monooxit NO : 0 t° +2 N2 + O2 < > 2N 0 Trong phan iimg nay, sd oxi hoa cua nito tang tir 0 den -t-2, nita the hien tfnh khu Trong thien nhien, khi NO dugc tao thanh khi cd sam set (hinh 2.1). Hmh 2.1. Sdm set cung cd'p ndng lugng cho phdn dng gida Nj vd O2 tao thdnh NO 29 6 dieu kien thudng, khf NO khdng mau ket hgp ngay vdi oxi cua khdng khi, tao ra khf nito dioxit NO^ mau nau dd : +2 +4 2NO + O2 > 2NO2 Ngoai cac oxit tren, cdn cd cac oxit khae ciia nito nhu N,0, N^O^ NiOj, chiing khdng dieu che dugc bang tac dung true tiep giiia nita va oxi. IV- UNG DUNG Nguyen td nito la mdt trong nhiing thanh phan dinh dudng chfnh ciia thuc vat. Trong cdng nghiep, phan ldn lugng nito san xuai ra dugc diing de tdng hgp khf amoniac. tir dd san xuai ra axit nitric, phan dam, ... Nhieu nganh cdng nghiep nhu luyen kim, thuc pham, dien tu, ... sir dung nito lam mdi trudng tra. Nita long dugc ddng de bao quan mau va cac mSu vat sinh hgc khae. V - TRANG THAI TU NHIEN Trong tu nhien, nito tdn tai d dang tu do va dang hgp chai. 6 dang tu do. khf nito chie'm 78.16% the tfch ciia khdng khf, hoac gan dung cd the coi khf nito chie'm 4/5 the tfch cua khdng khf. Nita thien nhien la hdn hgp ciia hai ddngvi: ^^N (99.63%) va \^N (0,37%). O dang hgp chai. nito cd nhieu trong khoang chai natri nitrat NaNOj, vdi ten ggi la dietn tieu natri. Nito cdn cd trong thanh phan cua protein ddng vat va thuc vat. VI - Oli u CHE 1. Trong cong nghiep Nita dugc san xuat bang phuang phap chung cat phan doan khdng khi long. Sau khi da loai bd COj va hai nudc, khdng khf dugc hoa long dudi ap suat cao va nhiet do rat tha'p. Nang nhiet dg khong khi long den -196 °C thi nito sdi va dugc lay ra, cdn lai la oxi long, vi oxi long cd nhiet do sgi cao hon (-183 oC). Khi nita dugc van chuye'n trong cac binh thep, nen dudi ap suai 150 atm. 30 2 . Trong phong thi nghiem Mgt lugng nhd nito tinh kJiiei dugc dieu che bang each dun ndng nhe dung dich bao hoa mudi amoni nitrit: NH4NO2 -^ > N2t + 2H20 Mud'i nay kem ben, cd the dugc thay the bang dung dich bao hoa cua amoni clorua va natri nitrit : r^4Cl + NaNOj ^ ^ N2T + NaCl + 2H2O BAI TAP 1. Trinh bay cau tao ciia phan td N2. Vi sao d dieu kien thudng, nitd la mpt chai trd ? 6 dieu kien nao nitd trd nen hoat dpng hon ? 2. Nito khong duy tri sU ho ha'p, nito cd phai la khi doc khong ? 3. a) Cap cong thUc cua liti nitrua va nhdm nitrua la A. UN3vaAl3N. B. LijN vaAlN. C. Li2N3 va AI2N3. D. Li3N2 va AI3N2. b) Viet phuong trinh hoa hoc cua phan dng tao thanh liti nitrua va nhdm nitrua khi cho liti va nhom tac dung trUc tiep vdi nito. Trong cac phan dng nay nitd la chai oxi hoa hay chai khd ? 4. Nguyen td nito c6 sd oxi hoa la bao nhieu trong cac hgp chai sau : NO, NO2, NH3, NH4CI, N2O, N2O3, N2O5, Mg3N2 ? 5. Can lay bao nhieu lit khi nito va khi hidro de dieu che dugc 67,2 lit khi amoniac ? Biei rang the tich cua cac khf deu dupc do trong cung dieu kien nhiet dp, ap suai va hieu suai cua phan Ung la 25%. 31 AMONIAC VA MUOI AMONI & Biei cac tinh chai vat If, hoa hoc cua amoniac va mudi amoni. & Biei vai tro quan trong cua amoniac va muoi amoni trong ddi sdng va trong san xuai. A - AMONIAC I - CAU TAO PHAN TU Trong phan tir amoniac, nguyen tii N lien ket vdi ba nguyen tu hidro bang ba lien kei cgng hoa tri cd cue. Nhiing ddi electron dung chung lech ve phia nguyen tu nita ed dg am dien ldn hom. Phan tir NH3 cd cau tao hinh chdp vdi nguyen tu nita d dinh, day la mdt tam giac ma dinh la ba nguyen tir H (hinh 2.2). Trong phan tu NH3, nguyen tir N cdn cd mgt cap electron hoa tri cd the tham gia lien ket vdi nguyen tu khae. II-TiNH CHAT VAT Ll Amoniac la chai khi khdng mau, cd mui khai va xdc, nhe hon khdng khi. Khi amoniac tan rai nhieu trong nudc : 6 dieu kien thudng, 1 lit nudc hoa tan dugc khoang 800 lit khi amoniac. Thi nghiem : Nap day khi amoniac vao binh thuy tinh trong sudt, day binh bang niit cao su cd d'ng thuy tinh vudt nhgn xuyen qua. Nhiing dau d'ng thuy tinh vao mdt chau thuy tinh chua nudc cd pha them dung dich phe nolphtalein. Mgt lat sau, nudc trong chau phun vao binh thanh nhiing tia cd mau hdng (hinh 2.3). Dd la vi khi amoniac tan nhieu trong nudc lam giam ap suai trong binh va nudc bi hiit vao binh. Phenolphtalein chuyen thanh mau hdng, chumg td dung dich cd tfnh bazo. 32 Hinh 2.2. Sa dd cdu tqo ciia phdn tu NH^ VNH 3 HjO CO pha phenolphtalein H'.nh2.3,5,f/,od,a« cua amoniac trong ^f^^ Dung dich thu dugc ggi la dung dich amoniac. Dung dich amoniac dam dac thudng dung trong phdng thi nghiem cd ndng do 25% (D = 0,91 g/cm^). Ill - TINH CHAT HOA HOC 1. Tinh bazo yeu a) Tdc dung vdi nudc Khi tan trong nudc, NH3 ket hgp vdi ion H+ ciia nudc, tao thanh ion amoni NH4 va giai phdng ion hidroxit OH", lam cho dung dich cd tfnh baza va dan dien : NH3 + H2O ( > NH ; -I- OH Trong dung dich, amoniac la baza yeu. Cd the diing giay quy tim am de nhan biei khf amoniac, quy tfm se chuyen thanh mau xanh. b) Tdc dung vdi dung dich muoi Dung dich amoniac cd the tac dung vdi dung dich mudi ciia nhieu kim loai, tao thanh kei tiia hidroxit ciia cac kim loai dd. Thi du : AICI3-1- 3NH3 + 3H2O > Al(OH)3 i + 3NH4CI A13+ -1- 3NH3 + 3H2O > Al(OH)3 i + 3NH ; c) Tdc dung vdi axit Khf amoniac, ciing nhu dung dich amoniac, tac dung vdi dung dich axit tao ra mudi amoni. Thi du : NH3 + HCl > NH4CI amoni clorua 2NH3 + H2SO4 > (NH4)2S04 amoni sunfat 2. Tinh khu Trong phan tir amoniac. nita cd sd oxi hoa -3 , la sd oxi hoa thap nhat, vi vay amoniac cd (nb khu. Tinh chai nay dugc the hien khi amoniac tac dung vdi cac chai oxi hoa. 3 - HH11(C)-A 33 a) Tdc dung vdi oxi Amoniac chay trong oxi cho nggn lira mau vang. tao ra khi nito va hai nudc (hinh 2.4) : 4NH3 +30 T -> 2N2 +6H2O Hinh 2.4. Khi amoniac chdy trong oxi b) Tdc dung vdi clo Clo oxi hoa manh amoniac tao ra nita va hidro clorua : 2NH3 + 3CI2 > N2+ 6HC1 Ddng thdi NH3 kei hgp ngay vdi HCl tao thanh "khdi" trang NH4CI. IV - UNG DUNG Amoniac dugc sir dung chii yeu de san xuat axit nitric, phan dam nhu ure, amoni nitrat, amoni sunfat, ... ; dieu che hidrazin N2H4 iam nhien lieu cho ten lua. Amoniac long dugc diing lam chai lam lanh trong thiet bi lanh. 34 ^-HH11(C).B V - DIEU CHE 1. Trong phdng thi nghiem Khi amoniac dugc dieu che bang each dun ndng mudi amoni, thi du NH4CI, vdi Ca(0H)2 (hinh 2.5). Hinh 2.5. Dieu che'khi amoniac trong phong thi nghiem 2NH4CI + Ca(OH)2 -^-^ CaCl2 + 2NH3t + 2H2O De lam khd khf, ngudi ta cho khf amoniac vira tao thanh cd ISn hoi nude di qua binh dung vdi sdng (CaO). Khi mud'n dieu che nhanh mdt lugng nhd khi amoniac, ngudi ta thudng dun ndng dung dich amoniac dam dac. Trong cdng nghiep Khf amoniac dugc tong hgp tii nita va hidro theo phan ilng : N-, (k) + 3H, (k) ^ t",p. xt ^ 2NH3 (k) AH< 0 Day la phan umg thuan nghich va toa nhiet. Cac dieu kien ap dung trong cdng nghiep san xuai amoniac la : - Nhiet dg : 450 - 500 °C. 0 nhiet do thap hom, can bang hoa hgc tren chuyen dich sang phai lam tang hieu suai phan umg, nhung lai lam giam td'c do phan ung. - Ap suai cao, tii 200 den 300 atm. - Chai xiic tac la sat kim loai dugc trgn them AI2O3, K2O, ... Trong khf amoniac tao thanh cdn lin nita va hidro. Hdn hgp khi dugc lam lanh, chi cd amoniac hoa long va tach ra. Cdn nito va hidro chua tham gia phan iing lai dugc bd sung vao hdn hgp nguyen lieu ban dau. 35 B - MUOI AMONI Mudi amoni la chat tinh the' ion, gdm cation amoni NH^ va anion gd'c axit. Thi du : NH4CI (amoni clorua), (NH4)2S04 (amoni sunfat),... I - TfNH CHAT VAT Ll Tai ca cac mudi amoni deu tan nhieu trong nudc, khi tan dien li hoan toan thanh cac ion. lon NH4 khdng cd mau. II - TINH CHAT HOA HQC 1. Tcic dung v6i dung djch kidm Dung dich dam dac cua mud'i amoni phan umg vdi dung dich kiem khi dun ndng se cho khi amoniac bay ra. Thi dii : (NH4)2S04 + 2NaOH Phuang trinh ion nit ggn : N H ; + OH 2NH3t +2H20 + Na2S04 NH3T +H2O Dua vao tinh chat nay ngudi ta cd the nhan biet ion amoni va dieu che amoniac trong phdng thf nghiem. 2. Phcin ling nhi$t phan cac mudi amoni de bi phan huy bdi nhiet. • Mudi amoni chiia gdc axit khdng cd tinh oxi hoa khi dun ndng bi phan huy thanh amoniac. Thi dii : Tmh the NH4CI khi dugc dun ndng trong d'ng nghiem (hinh 2.6) se phan huy thanh khi NH3 va khi HCl : - TSm kinh ~NH4CI(r) - Khi NH3 va HCl -NH4CI(r) NH4CI (r) NH3 (k) + HCl (k) Hinh 2.; Su phdn huy cua NH -Cl 36 Khi bay len mieng dng gap nhiet do thap hom, hai khi nay lai hoa hgp vdi nhau tao lai tinh the NH4CI mau trang. Cac mudi amoni cacbonat va amoni hidrocacbonat bi phan huy dan dan ngay d nhiet do thudng giai phdng khf NH3 va khi CO2, khi dun ndng phan iing xay ra nhanh hon : (NH4)2C03 (r) > NH3 (k) + NH4HCO3 (r) NH4HC03(r) > NH3 (k) + CO2 (k) + H2O (k) Trong thuc te, ngudi ta thudng dung mudi NH4HCO3 de lam xd'p banh. • Mudi amoni chda gd'c cua axit cd tinh oxi hoa nhu axit nitra, axit nitric khi bi nhiet phan cho ra N2, NjO (dinito oxit). Thidu: NH4NO2 ^ ^ N2 + 2H2O NH4NO3 -^--^ N2O + 2H2O Nhiing phan iing nay dugc sir dung de dieu che'cac khf N, va N2O trong phdng thf nghiem. BAI TAP 1. Md ta va giai thfch hien tugng xay ra trong thf nghiem chdng minh rang amoniac tan nhieu trong nudc. 2. Hoan thanh sd do chuyen hoa sau day va viet cac phUdng trinh hoa hgc : ixu- A +H,0 _ ... . +HCI „ +NaOH ,^, , , +HN0, ^ Khi A rf—> Dung djch A 7^^—> B 7^ > Khi A ' > C > '° -> D + HoO (5) ' '^ "2 ^ Biei rang A la hgp chai cua nitd. 3. Hien nay, de san xuai amoniac, ngudi ta dieu che nito va hidro bang each chuyen hoa CO xuc tac mpt hdn hpp gdm khong khi, hoi nUdc va khi metan (thanh phan chinh ciia khi thien nhien). Phan dng giCra khi metan va hoi nUdc tao ra hidro va cacbon dioxit. De loai khi oxi va thu khi nitd, ngudi ta ddt khf metan trong mpt thiet bi kin chda khong khi. Hay viet cac phuong trinh hoa hpe cua phan Ung dieu che khi hidro, loai khf oxi va tdng hop khi amoniac. 37 4. Trinh bay phuong phap hoa hoc de phan biet cac dung dich : NH3, Na2S04, NH4CI, (NH4)2S04. Viet phuong trinh hoa hpe cua cac phan Ung da diing. 5. Mudn cho can bang cua phan dng tdng hpp amoniac chuyen dich sang phai, can phai ddng thdi : A. tang ap suai va tang nhiet dp. B. giam ap suai va giam nhiet dp. C. tang ap suai va giam nhiet dp. D. giam ap suai va tang nhiet dp. 6. Trong phan Ung nhiet phan cac mudi NH4NO2 va NH4NO3, sd oxi hoa cua nito bien ddi nhu the nao ? Nguyen td nito trong ion nao cua mudi ddng vai trd chai khd va nguyen td nitd trong ion nao cua mudi dong vai trd chai oxi hoa ? 7. Cho dung djch NaOH dU vao 150,0 ml dung dich (NH4)2S04 1,00M, dun ndng nhe. a) Viet phuong trinh hoa hgc d dang phan td va dang ion rut gpn. b) Tinh the tich khf (dktc) thu dugc. 8. Phai dung bao nhieu lit khi nito va bao nhieu lit khi hidro de dieu che 17,0 gam NH3 ? Biet rang hieu suai chuyen hoa thanh amoniac la 25,0%. Cac the tich khi dupc do d dktc. A. 44,8 lit N2 va 134,4 lit H2 B. 22,4 lit N2 va 134,4 lit H2 C. 22,4 lit N2 va 67,2 lit H2 D. 44,8 lit N2 va 67,2 lit H2 38 Bdi W 9 r AXIT NITRIC VA IV1UOI NITRAT & Biei cau tao phan tu, tfnh chai vat li va hieu tinh chai hoa hoc cua axit nitric, tfnh chai cua cac mudi nitrat. !/: Biei phuang phap di&u che axit nitric trong phong thi nghiem va trong cong nghiep. A - AXIT NITRIC I - CAU TAO PHAN TU n Axit nitric (HNO3) cd cdng thiic cau tao ; ^ H-O- N O (Mui ten trong cdng thdc eau tao tren eho biet cap electron lien ket chi do nguyen tir nita cung cap). Trong hgp chai HNO3, nito cd sd oxi hoa cao nhai la -i-5. II - TINH CHAT VAT Ll Axit nitric tinh khiet la chat long, khdng mau, bdc khdi manh trong khdng khf am, D = 1,53 g/cm^. Axit nitric kem ben. Ngay d dieu kien thudng, khi cd anh sang, dung dich axit nitric dac da bi phan huy mdt phan giai phdng khf nita dioxit. Khi nay tan trong dung dich axit, lam cho dung dich cd mau vang. Axit nitric tan trong nudc theo bai ki ti le nao. Trong phdng thf nghiem thudng cd loai HNO3 dac ndng do 68%, D = 1,40 g/cm^. III - TINH CHAT HOA HOC 1. Tinh axit Axit nitric la mdt trong cac axit manh nhai, trong dung dich loang nd phan li hoan toan thanh ion H+ va ion NO3. Dung dich HNO3 lam dd quy tim ; tac dung vdi oxit bazo, bazo va mudi ctia axit yeu hern tao ra mudi nitrat. 39 Thi du : CuO + 2HNO3 ^ Cu(N03)2 + H2O Ba(0H)2 + 2HNO3 * Ba(N03)2 + 2H2O CaC03 + 2HNO3 ^ Ca(N03)2 + CO2 + H2O 2. Tinh oxi hoa Axit nitric la mdt trong nhiing axit cd linh oxi hoa manh. Tuy thugc vao ndng dg cua axit va do manh yeu cua chai khir, ma HNO3 cd the' bi khir de'n cac san pham khae nhau ciia nito. a) Tdc ditng vdi kim loai Axit nitric oxi hoa dugc hau het cac kim loai, ke ca kim loai cd tfnh khu yeu nhu Cu, Ag, ..., trd Pt va Au. Khi dd, kim loai bi oxi hoa de'n miic oxi hoa cao va tao ra mudi nitrat. Thdng thudng, neu diing dung dich HNO3 dac +4 +2 thi san pham la NO2 , cdn dung dich loang thi tao thanh NO. 0 +5 +2 +4 Thidu: Cu + 4HN03(dac) > Cu(N03)2 + 2N02 t + 2H2O 0 +5 +2 +2 3Cu-f-8HN03(loang) > 3Cu(N03)2+2N0 t +4H2O +5 Vdi cac kim loai cd tinh khir manh nhu Mg, Al, Zn, ..., HNO3 loang cd the bi +1 0 -3 khu de'n N2O, N2 hoac NH^NO^. Trong dung dich HNO3 dac, ngugi, Al va Fe bi thu dgng hoa do tao ra mgt ldp mang oxit ben, bao ve cho kim loai khdi tac dung cua cac axit. Vl vay, cd the dung binh lam bang nhdm hoac sat de dung HNO3 dac. b) Tdc dung vdi phi kim Khi dun ndng, HNO3 dac cd the oxi hoa dugc cac phi kim nhu C, S, P, ... 0 +5 o +6 +4 Thidu: S+6HN03(dac) -^~^ H2SO4 +6NO2T + 2H2O 40 c) Tdc diing vdi hgp chdt HNO3 dac cdn oxi hoa dugc nhieu hgp chai vd co va hiiu ca. Vai, gia'y, mun cua, diu thdng, ... bi pha huy hoac bdc chay khi tie'p xuc vdi HNO3 dac. IV - UNG DUNG Axit nitric ed rai nhieu umg dung quan trgng. Phan ldn axit nitric san xuai ra dugc dung de dieu che phan dam NH4NO3, Ca(N03)9,... Ngoai ra, axit nitric cdn dugc dung de san xuai thud'c nd, thi du : trinitrotoluen (TNT) ; thud'c nhudm ; dugc pham ; ... V - DIEU CHE 1. Trong phdng thi nghiem De dieu che mgt lugng nhd axit nitric trong phdng thi nghiem, ngudi ta dun hdn hgp natri nitrat hoac kali nitrat ran vdi axit sunfuric dac (hinh 2.7) ; NaNOj + H2SO4 -> HNO3 + NaHS04 Nirac da "HNO, Hinh 2.7 Dieu che axit nitric trong phdng thi nghiem Hai HNO3 thoat ra dugc dan vao binh iam lanh va ngung tu d dd. 2. Trong cong nghiep Phuang phap hien dai san xuai axit nitric tir amoniac gdm ba giai doan a) Oxi hoa khf amoniac bang oxi khdng khf thanh nita monooxit (NO) : - 3 4NH 3 -50^ 850-900 °C Pt -> 4N 0 +6H2O AH<0 41 Phan ling nay dugc thuc hien d 850 - 900 °C, cd mat chat xuc tac platin. b) Oxi hoa nita monooxit thanh nita dioxit bang oxi khdng khi d dieu kien thudng : 2NO + O2 ^ 2NO2 c) Nita dioxit tac dung vdi nudc va oxi thanh axit nitric : 4NO2 + O2 + 2H2O > 4HNO3 Dung dich HNO3 thu dugc thudng cd ndng dg 52 - 68%. De cd axit nitric vdi ndng do cao hon 68%, ngudi ta chung eat axit nay vdi H2SO4 dam dac. B - MUOI NITRAT Mudi cua axit nitric dugc ggi la nitrat, thi du : natri nitrat NaN03, bae nitrat AgN03, ddng(ll) nitrat Cu(N03)2, ... I - TINH CHAT CUA MUOI NITRAT 1. Tai ca cac mudi nitrat deu de tan trong nudc va la chai dien li manh. Trong dung dich loang, chung phan li hoan toan thanh cac ion. Thi dii : NaNOj > Na+ -t- NO3 2. Phan irng nhiet phan Cac mud'i nitrat de bi nhiet phan huy, giai phdng oxi. Vi vay, d nhiet dd cao cac mudi nitrat cd tinh oxi hoa manh. Cac mudi nitrat cua kim loai boat ddng manh (kali, natri,...) bi phan huy tao ra mudi nitrit va O2. Thi du : 2KNO3 ^- ^ 2KNO2 -1- O2T Mudi nitrat eua magie, kem, sat, chi, ddng, ... bi phan huy tao ra oxit cua kim loai tuong iing, NO2 va O2. 42 Thi du : 2Cu(N03)2 "^ ^ 2CuO + 4N02t + O2T Mudi nitrat cua bae, vang, thuy ngan,... bi phan buy tao thanh kim loai tuomg ling, NO, va Oj : 2AgN03 -^ ^ 2Ag + 2N02T +02 ! 3. Nhan hiet ion nitrat Trong mdi trudng trung tinh, ion NO3 khdng cd tinh oxi hoa. Trong mdi trudng axit, ion NO3 the hien tinh oxi hoa gid'ng nhu HNO3. Vi vay, de nhan biet ion NO3 trong dung dich, ngudi ta them mdt ft vun ddng va dung dich H2SO4 loang vao rdi dun ndng nhe hdn hgp. Phan iing tao thanh dung dich mau xanh, khi NO khdng mau thoat ra bi oxi eua khdng khi oxi hoa thanh khf NO2 mau nau dd. 3Cu + 8H+ +2NO3 t° ^ 3Cu2+ + 2N0 t + 4H2O (dd mau xanh) 2N0 + O2 (khong khO > 2NO2 (mau nau do) II - UNG DUNG Cae mudi nitrat duge sir dung chu yeu lam phan bdn hoa hgc (phan dam) trong ndng nghiep, thi du : NH4NO3, NaN03, KNO3, Ca(N03)2. Kali nitrat edn dugc sir dung de che thud'c nd den (thud'c nd cd khdi). Thudc nd den chda 75% KNO3, 10% S va 15% C. C - CHU TRINH CUA NITO TRONG TU NHIEN Nguyen td nito rai can cho su sd'ng tren Trai Dai. Trong tu nhien ludn ludn dien ra cae qua trinh chuyen hoa nito tii dang nay sang dang khae theo mgt chu trinh tuan hoan khep kin (hinh 2.8). 43 Hinh 2.8. Chu trinh ctia nito trong tif nhien 1. Cay xanh ddng hoa nita chu yeu dudi dang mudi nitrat va mudi amoni, chuyen hoa thanh protein thuc vat. Dgng vat ddng hoa protein thuc vat, tao ra protein dgng vat. Cac chai hiiu co do ddng vat bai tiet ra (phan, nudc tieu, ...) ciing nhu xac chei dgng vat bi phan buy lai chuyen thanh cac hgp chai hiru ca chda nito. Nhd nhirng loai vi khuan khae nhau ed trong dai, mdt phan cac hgp chat nay chuyen hoa thanh amoniac, rdi tir amoniac chuyen hoa thanh mudi nitrat, phan cdn lai bi thoat ra d dang nita tu do bay vao khi quyen. Khi cac chai hiiu co (than gd, than da, than bun, ...) bi ddt chay, nita tu do ciing dugc thoat ra. 2. Trong thuc te, cd mgt sd qua trinh tu nhien cho phep chuyen hoa mdt phan nito d dang tu do thanh dang hgp chai. Trong mua gidng, khi cd su phdng dien do sam set, mdt phan nita tu do trong khi quyen kei hgp vdi oxi tao thanh NO, rdi chuyen hoa thanh HNO3 va theo nude mua tha'm vao dai. HNO3 chuyen thanh mudi nitrat khi ket hgp vdi cac mudi cacbonat, thf du canxi cacbonat (ed trong dai). Mdt sd loai vi khuan, dac biet la cac vi khuan cd dinh dam sdng d re cay hg dau, ed kha nang ha'p thu nita tii khi quyen, rdi chuyen hoa thanh cac hgp chai chda nito. 3. De tang nang suai mua mang, lugng nita chuyen td khf quyen vao dai van khgng the' du. Vi vay ngudi ta phai bdn cho dai nhirng hgp chai chua nito dudi dang cac loai phan bdn hiru co va vd co. 44 BAI TAP 1. Viei cong thdc electron, cdng thdc cau tao cua axit nitric. Cho biet nguyen td nito co hoa tri va sd oxi hoa bao nhieu ? 2. Lap cac phuong trinh hoa hpe : a) Ag + HNO3 (dac) b) Ag + HNO3 (loang) c) Al + HNO3 d) Zn + HNO3 e) FeO + HNO3 g) Fe304 + HNO3 N02t NOT N2O T NH4NO3 NOT NOT + ? + ? + ? + ? + ? + ? + 9 + ? + Fe(N03)3 + Fe(N03)3 + ? + ? 3. Hay chi ra nhdng tinh chai hoa hpe chung va khae biet gida axit nitric va axit sunfuric. Viet cac phUdng trinh hoa hpe de minh hoa. 4. a) Trong phuong trinh hoa hpe cua phan dng nhiet phan sat(lll) nitrat, tdng cac he sd bang bao nhieu ? A. 5 8.7 C. 9 D. 21 b) Trong phUdng trinh hoa hoc cija phan dng nhiet phan thuy ngan(il) nitrat, tdng cac he sd bang bao nhieu ? A. 5 B. 7 • C. 9 D. 21 5. Viei phuong trinh hoa hpe cua cac phan dng thUc hien day chuyen hoa sau day : NO2 — ^ HNO3 — ^ Cu(N03)2 '^' ) Cu(0H)2 — ^ Cu(N03)2 _i5L ^ CuO -^ ^ Cu -^ ^ CUCI2 6. Khi hoa tan 30,Og hdn hop dong va d6ng(ll) oxit trong 1,50 lit dung dich axit nitric 1,00M (loang) thay thoat ra 6,72 lit nito monooxit (dktc). Xac dinh ham lupng phan tram cua d6ng(ll) oxit trong hdn hgp, ndng do moi cua ddng(ll) nitrat va axit nitric trong dung dich sau phan dng, biei rang the ti'ch dung dich khdng thay ddi. 7. De dieu che 5,000 tan axit nitric nong dp 60,0% can dung bao nhieu tan amoniac ? Biet rang sU hao hut amoniac trong qua trinh san xuai la 3,8%. 45 PHOTPHO £7 Biei vi tri cua photpho trong bang tu4n hoan. ( ^ Biei cac dang thu hinh, tinh chai vat li va tinh chai hoa hoc cua photpho, each dieu che va nhung ung dung cua nguyen td nay. I - V! TRI VA CAU HiNH ELECTRON NGUYEN TU Photpho d d thd 15, nhdm VA, chu ki 3 trong bang tuan hoan. ca'u hinh electron nguyen tu cua photpho : Is- 2s- 2p^ 3s^ 3p-' Do ldp ngoai cung cd 5 electron, nen trong cac hgp chai, hoa tri cua photpho ed the la 5. Ngoai ra, trong mgt sd hgp chai, photpho cdn cd hoa tri 3. II -TINH CHAT VAT Ll Photpho ed the' tdn tai d mgt sd dang thii hinh khae nhau, nhung quan trgng ban ca la photpho trang va photpho dd (hinh 2.9). 1. Photpho trdng Photpho trang la chai ran trong sudt, mau trang hoac hai vang, trdng gid'ng nhu sap, ed cau true mang tinh the phan tu. Trong tinh the, nhirng phan tir P4 (hinh 2.10) nam d nut mang va lien ket vdi nhau bang luc tuomg tac yeu. a) Photpho trBng •'•'^ 1 iss^fm^ ^ ^ ^^•H b) Photpho do Hmh 2.9 Hmh 2.10 Md hinh phdn tu P. 46 Do dd, photpho trang mem, de ndng chay (t^^ = 44,1°C). Photpho trang khdng tan trong nudc, tan trong mdt sd dung mdi hiru ca nhu C^Hg, CS2,...; rat ddc va gay bdng nang khi rai vao da. Photpho trang bdc chay trong khdng khi d nhiet dg tren 40°C, nen dugc bao quan bang each ngam trong nudc. O nhiet dg thudng, photpho trdng phat quang mau luc nhat trong bdng tdi. Khi dun ndng den nhiet do 250 "C va khdng cd khdng khi, photpho trang chuyen dan thanh photpho dd la dang ben ban. 2. Photpho do Photpho dd la chat bgt mau dd, de hut am va chay riia, ben trong khdng khi d nhiet do thudng va khdng phat quang trong bdng tdi, khdng tan trong cac dung mdi thdng thudng, ehi bdc chay d nhiet do tren 250 °C. Khi dun ndng khong ed khdng khf, photpho dd chuyen thanh hoi, khi lam lanh thi hai dd ngung tu lai thanh photpho trang. Photpho dd cd cau true polime (hinh 2.11), nen khd ndng chay va khd bay hoi hom photpho trang. Hinh 2.11. Cd'u triic polime cua photpho do III - TINH CHAT HOA HOC Photpho la phi kim tuang dd'i hoat ddng. Photpho trang hoat ddng hoa hgc manh hon photpho dd. Trong cac hgp chai, photpho cd sd oxi hoa -3 , -i-3 va -H5. Do dd, khi tham gia phan dng hoa hgc photpho the hien tfnh oxi hoa hoac tfnh khu 1. Tinh oxi hoa Photpho the' hien tinh oxi hoa khi tac dung vdi mdt sd kim loai hoat ddng tao ra photphua kim loai. Thi du : 0 ,0 - 3 2 P + 3Ca —^—> Ca3P2 canxi photphua 2. Tinh khu Photpho the' hien tfnh khu khi tac dung vdi cac phi kim hoat dgng nhu oxi, halogen, luu huynh,... va cac hgp chai ed tfnh oxi hoa manh khae. 47 Photpho chay dugc trong khdng khf khi ddt ndng 0 thieu oxi : 4P -i- 30 . +3 - - ^ 2P2O 3 diphotpho trioxit 0 ,0 +5 duoxi: 4P-h502 —^ ^ 2P2O5 diphotpho pentaoxit Photpho tac dung de dang vdi khf clo khi ddt ndn^ 0 ,0 +3 thieu clo: 2P + 3CI2 — ^ 2PCI3 photpho triclorua 0 ,0 +5 duelo: 2P + 5CI2 -^- > 2PCI5 photpho pentaclorua IV - UNG DUNG Phan ldn photpho san xuat ra dugc dung de san xuai axit photphoric, phan cdn lai chu ye'u dung trong san xuai diem. Ngoai ra, photpho cdn dugc dung vao muc dich quan su : san xuai bom, dan chay, dan khdi, ... V - TRANG THAI TU NHIEN Trong tu nhien, khdng gap photpho d trang thai tu do VI nd kha boat ddng ve mat hoa hgc. Hai khoang vat chinh cua photpho la photphorit Ca3(P04)2 va apatit 3Ca3(P04)2.CaF2 (hinh 2.12). a) Apatit Hinh 2.1 2, Mgt so khodng vdt cua photpho b) Photphorit 48 Nude ta cd md apatit d Lao Cai, mdt sd md photphorit d Thai Nguyen, Thanh Hoa, ... Ngoai ra, photpho cd trong protein thuc vat ; trong xuang, rang, bap thit, te bao nao, ... cua ngudi va ddng vat. VI - SAN XUAT Trong cdng nghiep, photpho dd dugc san xuai bang each nung hdn hgp quang photphorit (hoac apatit), cat va than cdc d 1200 °C trong Id dien. Hai photpho thoat ra dugc ngung tu khi lam lanh, se thu dugc photpho trang d dang ran. BAI TAP 1. Neu nhumg diem khae nhau ve tinh chai vat li gida P trang va P dd. Trong dieu kien nao P trang chuyen thanh P do va ngupc lai ? 2. Lap phUdng trinh hoa hpe cija cac phan dng sau day va cho biet trong cac phan dng nay, P cd tinh khd hay tinh oxi hoa : P + O2 P + CI2 P + S P + S P + Mg P + KCIO3 P2O5 PCU P2S3 P2S5 Mg3P2 P2O5 + KCl Thi nghiem d hinh 2.13 chdng minh kha nSng bdc chay khae nhau cua P trang va P dd. Hay qii.i'i sat. md ta va giai thich hien tUdng xay ra trong f^r n jhiem. Viet phuong trinh hoa hpe cua phan uiiy xay ra. Hinh 2.13. Thi nghiem chung minh khd ndng hoc chdy khdc nhau ciia P trdng vd P do 4 - HH11(C)-A 49 Neu nhung dng dung cua photpho. NhUng dng dung dd xuai phat tU tinh chai gi cua photpho ? Dot chay hoan toan 6,2 g photpho trong oxi dU. Cho san pham tao thanh tac dung vda du vdi dung djch NaOH 32% tao ra mudi Na2HP04. a) Viei phuong trinh hoa hpe cua cac phan dng xay ra. b) Tinh khdi lupng dung djch NaOH da dung. c) Tinh nong dp phan tram cua mudi trong dung dich thu dupc sau phan dng. Tif lieu VAI TRO SINH HOC CUA PHOTPHO Photpho rai can cho ngudi va ddng vat. Trong cathe ngudi, khoang 90% photpho tap trung d xuang, khoang 10% tap trung a cac ca, gan 1% a cac te bao nao (dudi dang cac hpp chai vd co va huu ca). O cac co, gan, nao va cac bp phan khae cua ca the, photpho cd dudi dang cac photphat va cac este cua axit photphoric. Vien sT ngudi Nga A.E. Fecman (1883-1945) gpi photpho la "nguyen td cua su sdng va tu duy". Ngudi lao dpng tri dc can luang photpho nhieu han de khdng bi suy mdn cac te bao than kinh giu chuc nang chuyen tai y nghi. Ca the thieu photpho se giam kha nang lam viec, loan than kinh chuc nang va pha huy su trao ddi chai. An cac loai rau, qua nhuxa laeh, dd, ca rdi, ca chua, ca tim, dt ngpt, dau tay, ma, ... se bd sung cho ca the luang photpho bi thie'u hut. Cac thuc pham giau photpho cd ngudn gd'c dpng vat gdm cd thit, dc, gan bd, ca, trdng, cac san pham sua, ... 50 4-HH11(C).B Bai W 11 r AXIT PHOTPHORIC VA MUOI PHOTPHAT & Biei dupc ca'u tao phan t d tinh chai vat If, hieu tfnh chai hoa hoc cua axit photphoric, tinh chai cua cac mudi photphat. & Biei duac nhung ung dung va phuang phap dieu che axit photphoric, ung dung va each nhan biei ion photphat. A - AXIT PHOTPHORIC I - CAU TAO PHAN T U Axit photphoric (H3PO4) cd cdng thuc cau tao : H-0 ^ H - O P= 0 H-O- ^ Trong hgp chai H3PO4, photpho ed sd oxi hoa eao nhai la -i-5. II - TINH CHAT VAT Ll Axit photphoric la chai tinh the trong sudt, ndng chay d 42,5 °C, rai hao nudc nen de chay rua, tan trong nudc theo bai ki ti le nao. Axit photphoric thudng dung la dung dich dac, sanh, khdng mau, cd ndng dg 85%. III - TINH CHAT HOA HOC 1. Axit photphoric la axit ba nac, ed do manh trung binh, ed tai ca nhirng tfnh chai chung cua axit. Trong dung dich nude, nd phan li theo tumg nac : Nad 1 ; H3PO4 ( > H+ +H2PO4 Nad 2 : H2PO4 ( > H" +HPO4 Nac 3 : HPOf < > H^ +P0^" 51 Su phan li chu yeu xay ra theo nac 1, nad 2 kem horn va nad 3 rai ye'u. Nhu vay, trong dung dich axit photphoric cd cac ion H+, ion dihidrophotphat H2PO4 ion hidrophotphat HP04~ , ion photphat P04~ va cac phan tu H3PO4 khdng phan li (khdng ke eae ion H+ va OH" do nude phan li ra). 2. Khi tac dung vdi dung dich kiem, tuy theo lugng chai tac dung ma axit photphoric tao ra mudi axit, hoac mudi trung hoa, hoae hdn hgp cac mudi dd. Thi du : H3PO4 + NaOH > NaH2P04 + H2O H3P04-^2NaOH > Na2HP04 + 2H2O H3PO4 + 3NaOH > Na^PO^ + 3H2O 3. Khae vdi axit nitric, axit photphoric khgng cd tinh oxi hoa. IV - DIEU CHE 1. Trong phong thi nghiem Axit photphoric duge dieu che bang each dung axit nitric dae oxi hoa photpho : P + 5HN03(dac) — ^ H3PO4 + 5NO2 + H2O 2. Trong cong nghiep Cho axit sunfuric dae tac dung vdi quang photphorit hoac quang apatit : Ca3(P04)2 + 3H2SO4 (dac) -^—^ 2H3PO4 + 3CaS04 i Axit H3PO4 tao thanh duge tach khdi ket tua CaS04 bang each lgc, sau dd dugc cd dac. Axit H3PO4 san xuat bang phuang phap nay khdng tinh khiet. De' san xuai axit H3PO4 ed do tinh khiet va ndng dg cao ban, ngudi ta ddt chay photpho de thu P20g, rdi cho P2O5 tac dung vdi nudc : 4P + 5O2 —^ 2P2O5 P2O5 + 3H2O > 2H3PO4 V - UNG DUNG Mdt lugng ldn axit H3PO4 loai ki thuat dugc dung de dieu che mudi photphat va de san xuai phan lan, hgp chai co photpho (lam thud'c tru sau),... H3PO4 tinh khiei dugc dung trong cgng nghiep dugc pham. 52 B - MUOI PHOTPHAT Mudi photphat la mudi cua axit photphoric. Axit photphoric tac dung vdi dung dich kiem, tao ra ba loai mudi : Mudi dihidrophotphat : NaH2P04, NH4H2PO4, Ca(H2P04)2, ... Mudi hidrophotphat : Na2HP04, (NH4)2HP04, CaHP04, ... Mudi photphat trung hoa : Na3P04, (NH4)3P04, Ca3(P04)2, ... I - TINH TAN Cae mudi trung hoa va mudi axit cua kim loai natri, kali va amoni deu tan trong nudc. Vdi cae kim loai khae, chi cd mudi dihidrophotphat la tan dugc, ngoai ra deu khdng tan hoac it tan trong nudc. II - NHAN BIET ION PHOTPHAT Thude thu de nhan biet ion PO4 trong dung dich mudi photphat la bae nitrat. Thi nghiem Them 3- 4 gigt dung dich bae nitrat vao 5- 6 gigt dung dich natri photphat dung trong mdt dng nghiem nhd. Ket tua mau vang xuai hien ngay lap tdc. Kei tua nay khdng tan trong nudc, nhung tan trong dung dich axit nitric loang. Phuomg trinh ion riit ggn : 3Ag+ +P0 ^ > Ag3P04i (mau vang) BAI TAP 1. Viei phuang trinh hoa hoc dang phan tdva dang ion rut ggn cua phan dng gida H3PO4 vdi lugng du cua : a) BaO b) Ca(0H)2 c) K2CO3 2. Neu nhdng diem gidng nhau va khae nhau ve tinh chai hoa hpe gida axit nitric va axit photphoric. Dan ra nhdng phan dng hoa hoc de minh hoa. 53 3. Phuang trinh dien li tdng cdng cua H3PO4 trong dung dich la : H3PO4 7 > 3H*+ PO^" Khi them HCl vao dung dich, A. can bang tren chuyen dich theo chieu thuan. B. can bang tren chuyen dich theo chieu nghich. C. can bang tren khdng bi chuyen djch. D. nong dp PO4" tang len. 4-. Lap cac phuang trinh hoa hpe sau day : a) H3PO4 —> 1 moi b) H3PO4 1 moi C) H3PO4 2 moi d) H3PO4 2 moi + + + + K2HPO4 1 moi Ca(0H)2 1 moi Ca(0H)2 1 moi Ca(0H)2 3 moi 5L De thu dupe mudi photphat trung hoa, can lay bao nhieu ml dung dich NaOH 1,00M cho tac dung vdi 50,0 ml dung dich H3PO4 0,50M ? 54 PHAN BON HOA HOC & Biei cay trdng can nhung nguyen td dinh duang nao. &Bie t thanh phan hoa hoc cua cac loai phan dam, phan lan, phan kali, phan phuc hpp,... va each dieu che cac loai phan bdn nay. Phan bdn hoa hgc la nhirng hoa chai cd chda cac nguyen td dinh dudng, dugc bdn cho cay nham nang eao nang suai mua mang. Cay ddng hoa duge C, H, O td CO2 cua khdng khi va td nude trong dai, edn ddi vdi cac nguyen td khae thi cay hap thu td dai. Dai trdng trgt bi ngheo dan cac nguyen td dinh dudng, vi vay can bdn phan de bd sung cho dai nhiing nguyen td dd. Cd ba loai phan bdn hoa hgc chinh thudng dung la phan dam, phan lan va phan kaU. I - PHAN DAM Phan dam cung cap nito hoa hgp cho cay dudi dang ion nitrat NO3 va ion amoni NH4 . Phan dam cd tac dung kich thieh cac qua trinh sinh trudng, lam tang ti le cua protein thuc vat. Do dd, phan dam giup cho cay phat trien nhanh, cho nhieu hat, cu, qua. Do dinh dudng cua phan dam duge danh gia theo ti le phan tram ve khd'i lugng cua nguyen td nito. 1. Phan dam amoni Dd la cae mudi amoni NH4CI, (NH4)2S04, NH4NO3, ... Cac mudi nay dugc dieu che khi cho amoniac tac dung vdi axit tuomg dng. Thi du : 2NH3 + H2SO4 > (NH4)2S04 2. Phan dam nitrat Dd la eae mud'i nitrat: NaN03, Ca(N03)2,... Cac mudi nay dugc dieu che bang phan ung giua axit nitric va mudi cacbonat. Thi du : CaC03 + 2HNO3 ^ Ca(N03)2 + CO2 + H2O 55 3. Ure Ure (NH2)2CO (chda khoang 46%N), la loai phan dam tdi nhai, dugc dieu ehe bang each cho amoniac tac dung vdi CO2 d nhiet do 180 - 200 °C, dudi ap suat khoang 200 atm : Hinh 2.14. Phdn ure CO2 + 2NH3 ' '^ ) (NH2)2CO + H2O Ure la chai rdn mau trdng (hinh 2.14), tan tdi trong nudc. Trong dai, dudi tac dung cua vi sinh vat, ure bi phan buy cho thoat ra amoniac, hoac chuyen dan thanh mudi cacbonat khi tac dung vdi nudc : (NH2)2CO + 2H2O > (NH4)2C03 Cac loai phan dam tren day bi chay nudc do hut hai am td khf quyen, nen can phai bao quan d nai khd rao. O nudc ta hien nay, ure dugc san xuai tai nha may phan dam Bdc Giang va nha may phan dam Phd My. II - PHAN LAN Phan lan cung cap photpho eho cay dudi dang ion photphat. Loai phan bdn nay can cho cay d thdi ki sinh trudng, thuc day cac qua trinh sinh hoa, trao ddi chai va trao ddi nang lugng cua cay. Do dinh dudng cua phan lan dugc danh gia theo ti le phan tram khdi lugng P2O5 tuomg dng vdi lugng P cd trong thanh phan eua nd. Nguyen lieu de san xuai phan lan la quang photphorit va apatit. Nhirng loai phan lan thudng dung la supephotphat, phan lan nung chay,... 1, Supephotphat Cd hai loai supephotphat : supephotphat dom va supephotphat kep. a) Supephotphat dem chua 14 - 20% P2O5, dugc san xuai bang each cho bdt quang photphorit hoac apatit tac dung vdi axit sunfuric dae : Ca3(P04)2 + 2H2SO4 (dac) > Ca(H2P04)2 + 2CaS04 i Supephotphat dan gdm 2 mudi Ca(H2P04)2 va CaS04. Cay trdng chi ddng hoa duge mudi dd tan Ca(H2P04)2 ; cdn CaS04 khdng tan trong nude, la phan khdng cd ich, lam rdn dai. 56 6 nudc ta hien nay, supephotphat dom dugc san xuat tai nha may supephotphat va hoa chai Lam Thao, Phu Thg. b) Supephotphat kep chua ham lugng P2O5 cao hom (40 - 50%), vi chi cd Ca(H2P04)2. Qua trinh san xuat supephotphat kep xay ra qua hai giai doan : dieu che axit photphoric va cho axit nay tac dung vdi photphorit hoac apatit : Ca3(P04)2 + 3H2SO4 > 2H3PO4 + 3CaS04i Ca3(P04)2 + 4H3PO4 > 3Ca(H2P04)2 2. Phan lan nung chay De san xuai phan lan nung chay, ngudi ta nung hon hgp bgt quang apatit, da xa van (thanh phan ehinh la magie silicat) va than cdc d nhiet do tren 1000 °C trong Id diing. San phdm ndng chay td Id ra duge lam ngudi nhanh bang nudc, sau dd say khd va nghien thanh bgt. Thanh phan chinh eua phan lan nung chay la hdn hgp photphat va silicat cua canxi va magie (chda 12 - 14% P20g). Cac mudi nay khdng tan trong nudc, nen chi thich hgp cho loai dai chua. O nudc ta hien nay, phan lan nung chay dugc san xuai d Van Dien (Ha Ndi) va mdt sd dia phuomg khae. Ill - PHAN KALI Phan kali cung cap eho cay trdng nguyen td kali dudi dang ion K+. Loai phdn bdn nay thuc day nhanh qua trinh tao ra cac chai dudng, bgt, chai xo, chai dau, tang cudng sue chd'ng ret, chdng sau benh va chiu han cua cay. Do dinh dudng eua phan kali dugc danh gia theo ti le phan tram khdi lugng K2O tuomg umg vdi lugng K cd trong thanh phan cua nd. Hai mudi kali clorua va kali sunfat dugc su dung nhieu nhat de lam phan kali. Tro thuc vat chda K2CO3 cung la mdt loai phan kali. IV - PHAN H6 N HOP VA PHAN PHUC HOP Dd la loai phan bdn chda ddng thdi mdt so nguyen td dinh dudng ca ban. • Phdn hdn hgp chda nita, photpho, kali dugc ggi chung la phdn NPK. Thi du, nitrophotka la hdn hgp eua (NH4)2HP04 va KNO3. Loai phan bdn nay la san phdm trdn ldn cac loai phan dan theo ti le N : P : K khae nhau, tuy theo loai dai va eay trdng. 57 • Phdn phi'cc hap la hdn hgp cac chai dugc tao ra ddng thdi bdng tuong tac hoa hgc cua cae chai. Thi du. amophot la hdn hgp cac mudi NH4H2PO4 va (NH4)2HP04, thu dugc khi cho amoniac tac dtang vdi axit photphoric. V - PHA N VI LUONG Phan vi lugng cung cap eho cay cac nguyen td nhu bo, kem, mangan, ddng, molipden. ... d dang hgp chai. Cay trdng chi can mdt lugng rat nhd loai phan bdn nay de tang kha nang kieh thich qua trinh sinh trudng va trao ddi chat, tang hieu lue quang hgp, ... Cac nguyen td tren ddng vai trd nhu nhiing vitamin cho thuc vat. Phan vi lugng dugc dua vao dat cung vdi phan bdn vd co hoac phan bdn hum co. Loai phan bdn nay ehi ed hieu qua cho timg loai eay va timg loai dai, dung qua lugng quy dinh se cd hai cho eay. BAI TAP 1. Cho cac mau phan dam sau day : amoni sunfat, amoni clorua, natri nitrat. Hay dung cac thudc thd thich hpp de phan biet chung. Viet phuong trinh hoa hpe cija cac phan dng da dung. 2. TU khdng khf, than, nudc va cac chat xuc tac can thiet, hay lap so do dieu che phan dam NH4NO3. 3. Mpt loai quang photphat cd chda 35% Ca3(P04)2. Hay tinh ham lupng phan tram P2O5 cd trong quang tren. 4. De san xuai mpt lugng phan bdn amophot da dung het 6,000.103 ^Q\ H3PO4. a) Tinh the tich khf amoniac (dktc) can dung, biet rang loai amophot nay cd tl le ve sd rnol n^iH^^H^po^: n(^H_^)^HPQ^ =1:1. b) Tinh khd'i lupng amophot thu dupc. 58 Bdi W of LUYEN TAP TINH CHAT CUA NITO, PHOTPHO VA CAC HOP CHAT CUA CHUNG & Nam vung cac tfnh chai cua nita, photpho ; amoniac va mudi amoni ; axit nitric va mudi nitrat ; axit photphoric va mudi photphat. & Nam vung cac phuang phap dieu che va ung dung cua nita, photpho va mpt so hgp chai quan trpng cua chung. & Ren luyen kT nang giai cac bai tap cua chuang. I - KIEN THUC CAN NAM VUNG C^u hinh electron : Is^ 2s2 2p3 Wt Photpho VI H Cau hinh electron : Is^ 2s2 2p6 3s2 3p3 Op am dien : 3,04 Do am dien : 2,19 Cau tao phan tuf: N s N Cac sd oxi hoa : -3, 0, +1, +2, +3, +4, +5 Dang thij hinh thudng gap ; P trang, P do Cac sd oxi hoa : -3, 0, +3, +5 +2 NO — nito the hien tinh khu +5 PjOg -. photpho the hien 0 / tinh khu N2 - - NH3 \ -3 Amoniac _^ nito the hien tinh oxi hoa P CaaPs-*- photpho the hien tinh oxi hoa P trang hoat ddng hoa hoc manh hon P do. Tan nhieu trong nudc tao thanh dung dich CO tinh bazo yeu. C6 tinh khd. 59 IVIuoi amoni Tan trong nUdc, la chai dien II manh. De bi nhi^t phan. Axit nitric (HNO3) Axit photphoric (H3PO4) H - O H-O- N H - 0 H - O p = o - La axit manh. - La chai oxi hoa manh. Tfnh oxi hoa +5 manh la do ion NO3 gay ra, nen san pham la cac hop chai khae nhau cija nitd. Mudi' nitrat - D l tan. - Trong dung djch axit, NO3 the hien tfnh oxi hoa. - Mud'i ran d l bi nhiet phan cho oxi thoat ra. - Ph^n Ung nhan biei : 3Cu + 8hr + 2N0 ; > - ^ 3Cu2+ + 2NOT +4H2O - La axit ba nac, do manh trung binh, tac dung vdi dung djch kiem cho ba loai mud'i : mot mud'i photphat trung hoa va hai mudi photphat axit. - Khdng the hien tfnh oxi hoa. IVIuoi photphat - Mud'i photphat trung hoa va photphat axit cija natri, kali, amoni d i tan. - Mud'i dihidrophotphat cua cac kim loai khae de tan. - Phan ufng nhan biet: 3Ag* + POl"- > Ag3P04 i (m^u vang) Ag3P04 tan trong dung dich HNO3 loang. 60 (dd mau xanh) 2N0 + O 2 > 2NO2 (mau nau do) II - BAI TAP 1. Hay cho biei sd oxi hoa cua N va P trong cac phan td va ion sau day : NH3, NH4 , NOi . NO3 . NH4HCO3, P2O3, PBrg, PO^" , KH2PO4, Zn3(P04)2. 2. Trong cac cdng thdc sau day, chpn cdng thdc hoa hoc dung cua magie photphua A. Mg3(P04)2 B. Mg(P03)2 C. Mg3P2 D. Mg2P207 3. a) Lap cac phUdng trinh hoa hpe sau day : NH3 + CI2 (du) - MLJ frA, f\ J. f^l riti'^ (OIJ) + '-''2 NH3 + CH3COOH - (NH4)3P04 - Zn(N03)2 - -> / -> t° ) t° —> N2 + ... NH4CI + ... H3PO4 + ... (1) (2) (3) (4) (5) b) Lap cac phuong trinh hoa hpe d dang phan td va dang ion rut gpn cua phan dng gida cac chai sau day trong dung dich : K3PO4 va Ba(N03)2 (1) Na3P04 va CaCl2 (2) Ca(H2P04)2 va Ca(0H)2 vdi ti le moi 1 : 1 (3) (NH4)3P04 + Ba(OH)2 (4) 4. Td hidro, clo, nito va cac hoa chai can thiet, hay viet cac phuong trinh hoa hpe (cd ghi ro dieu kien phan dng) dieu che phan dam amoni clorua. 61 5. Viet phuong trinh hoa hpe thuc hien cac day chuyen hoa sau day a) N, —^ ^ NH„ ^-^ ^ NH.NO, I 3 (3) 4 3 (4) (8) NO —^ ^ NO. T==^ HNO, 2 (7) 3 b) Photpho ^1 ^ B ^ ^ C -^ ^ P,0, 6. Hay dua ra nhUng phan dng da hpe cd sU tham gia cua don chai photpho, trong dd sd oxi hoa cua photpho : a) tang ; b) giam. 7. Khi cho 3,00 g hdn hpp Cu va Al tac dung vdi dung dich HNO3 dac dU, dun ndng, sinh ra 4,48 lit khi duy nhai la NO2 (dktc). Xac dinh phan tram khdi lugng cua moi kim loai trong hon hpp. 8. Cho 6,00 g P2O5 vao 25,0 ml dung dich H3PO4 6,00% (D = 1,03 g/ml). Tfnh nong dp phan tram cua H3PO4 trong dung dich tao thanh. 9. Can bdn bao nhieu kilogam phan dam amoni nitrat chda 97,5% NH4NO3 cho 10,0 hecta khoai tay, biet rang 1,00 hecta khoai tay can 60,0 kg nitd. 62 BAI THL/C HAN H 2 TINH CHAT CUA MO T SO HOP CHAT NITO, PHOTPHO E? Ren luyen ki nang thao tac thf nghiem an toan, chfnh xac. E? Lam cac thf nghiem chung minh : - Tfnh oxi hoa manh cua axit nitric. - Tfnh oxi hoa cua mudi kali nitrat. E? Thf nghiem phan biet mpt sd loai phan bdn hoa hpe. N OI DUN G THi NGHIEM VA CACH TIEN HANH Thi nghiem 1. Tinh oxi hoa ciia axit nitric Lay vao d'ng nghiem thd nhai 0,5 ml dung dich HNO3 dae (68%) va d'ng nghiem thd hai 0,5 ml dung dich HNO3 loang 15%. Cho vao mdi d'ng nghiem mdt manh nhd ddng kim loai. Niit cac dng nghiem bang bdng tam dung dich NaOH. Dun nhe d'ng nghiem thd hai. Quan sat mau cua khi bay ra va mau eua dung dich trong mdi dng nghiem. Giai thieh va viet cac phuong trinh hoa hgc. Thi nghiem 2. Tinh oxi hoa cua mudi kali nitrat ndng chay Lay mgt dng nghiem chiu nhiet khg va cap thang dung tren gia sat, rdi dat gia sat trong chau eat. Bd mdt it tinh the KNO3 vao dng nghiem va ddt cho mudi ndng chay. Khi mudi bat dau phan buy (nhin thay cac bgt khi xuat hien) vSn tie'p tue ddt ndng d'ng nghiem, ddng thdi dung kep sat bd mgt hdn than nhd da dugc ddi ndng dd vao d'ng. Quan sat su chay tiep tuc cua hdn than. Giai thich hien tugng va viei phuong trinh hoa hgc. Thi nghiem 3. Phan biet mgt sd loai phan bdn hoa hoc Cho cac miu phan bdn hoi hgc sau day : amoni sunfat, kali clorua va supephotphat kep. Lay mdi loai mdt it (ed bang hat ngd) vao tiing d'ng nghiem rieng biet. Cho vao mdi d'ng nghiem 4 - 5 ml nudc cat va lac nhe d'ng nghiem cho de'n khi cae chai tan hei. 63 a) Phdn dam amoni sunfat Lay khoang 1 ml dung dich eua mdi loai phan bdn vda pha che vao timg d'ng nghiem rieng. Cho vao mdi d'ng nghiem khoang 0,5 ml dung dich NaOH rdi dun ndng nhe. O d'ng nghiem nao chda dung dich amoni sunfat se cd khi bay len, khi nay lam xanh giay quy tim am. Viet phuong trinh hoa hgc cua phan dng xay ra dudi dang phuong trinh ion rut ggn. b) Phdn kali clorua vd phdn supephotphat kep Lay khoang 1 ml dung dich vda pha che cua kali clorua vao mgt d'ng nghiem va ciia supephotphat kep vao mgt d'ng nghiem khae. Nhd vai gigt dung dich AgN03 vao tdng d'ng. Phan biet hai loai phan bdn tren bang each quan sat hien tugng trong hai d'ng. Giai thich va viet phuong trinh hoa hgc cua cac phan dng. II-VIET TUONG TRINH 64 Chuong 3 CACBOiV - SHvIC & Vi tri ciia cacbon, silic trong hdng tudn hodn co lien quan nhu the ndo vai cau tao nguyen tu cm chiing ? & Cdc dan chat vd hap chat cm cacbon, silic co nhung tinh chat ca bdn ndo ? Gidi thich nhiing tinh chat do nhu the ndo tren casali thuyet dd hoc ? & Ldm the ndo dih che duac cacbon, silic vd mot so hap chd't quan trong ciia cdc nguyen td'ndy ? Nha may xi mang Hai Phong 5 - HH11(C)-A 65 CACBON & Biei duac tfnh chai cua cacbon lien quan nhu the nao vai cau hinh electron nguyen tu cua nd. & Biei dugc trang thai tu nhien, dieu che va ung dung cua cacbon. I - V! TRI VA CAU HINH ELECTRON NGUYEN TU Cacbon d d thd 6, nhdm IVA, chu ki 2 cua bang tuan hoan. Ca'u hinh electron cua nguyen tu cacbon la Is- 2s- 2p-, ldp ngoai eiing eo 4 electron, nen trong eae hgp chai nguyen tu cacbon ed the tao dugc tdi da 4 lien kei cdng hoa tri vdi cac nguyen tu khae. Cac so oxi hoa eua cacbon la -4, 0, +2 va +4. II -TiNH CHAT VAT Li Nguyen td cacbon cd mgt sd dang thu hinh la kim cuong, than ehi, fuleren, ... Chung khae nhau ve tinh chat vat li. Lien ket yeu giua cac lap a) b) c) Hinh 3.1. Cd'u true ciia : Tinh the kim cuang (a) : Tinh the than chi (b) ; Phdn tu fuleren C^Q (C) 1. Kim cuong Kim cuong la chai tinh the trong sudt, khong mau, khdng dSn dien, dan nhiet kem. Trong tinh the kim cuong (hinh 3.1a), mdi nguyen tu cacbon lien ket vdi bd'n nguyen tu cacbon lan can nam tren cac dinh cua hinh td dien deu bang bd'n 66 5 - HH11(C)-B lien kei cdng hoa tri ben. Mdi nguyen tu cacbon nam d dinh lai lien kdt vdi bdn nguyen tu cacbon khae. Do cau true nay ma kim cuong rat cdng, la chai cdng nhai trong tai ca cae chai. 2. Than chi Than ehi la chai tinh the' mau xam den. Tinh the' than chi cd cau true ldp (hinh 3.1b). Trong mgt ldp, mdi nguyen td cacbon lien ket cdng hoa tri vdi ba nguyen td cacbon lan can nam d dinh cua mdt tam giac deu. Cac ldp lan can lien kei vdi nhau bang tuong tac yeu, nen cac ldp de tach khdi nhau. Do cau true nay ma than chi mem, khi vach tren giay nd de lai vach den gdm nhieu ldp tinh the. 3. Fuleren Fuleren gdm cac phan td CgQ, C^Q, ... Phan td C^Q cd cau true hinh eau rdng, gdm 32 mat, vdi 60 dinh la 60 nguyen tu cacbon. Fuleren dugc phat hien nam 1985. Cac loai than dieu che nhan tao nhu than gd, than xuong, than mugi, ... dugc ggi chung la cacbon vo dinh hinh. liian gd, than xuong cd cau tao xd'p, nen ehung cd kha nang hap phu manh cac chai khi va chai tan trong dung dich. Ill - TINH CHAT HOA HOC Trong cac dang tdn tai cua cacbon, cacbon vd dinh hinh boat dgng hon ca ve mat hoa hgc. Tuy nhien, d nhiet do thudng cacbon kha tro, cdn khi dun ndng nd phan dng dugc vdi nhieu chai. Trong cac phan dng oxi hoa - khu, don chai cacbon cd the tang hoac giam so oxi hoa, nen nd the hien tinh khd hoac tinh oxi hoa Tuy nhien, tinh khu van la tinh chai chu yeu cua cacbon 1. Tinh khu a) Tdc dung vdi oxi Cacbon chay duge trong khdng khi, phan dng toa nhieu nhiet : 0 ,0+ 4 C +0 , -^- ^ COo 67 6 nhiet do eao, cacbon lai khu dugc CO, theo phan dng : COT + C > 2CO Do dd, san pham khi ddi cacbon trong khdng khi, ngoai khi COj edn ed mgt it khf CO. b) Tdc diing vdi hgp chdt O nhiet do cao, cacbon cd the' khu dugc nhieu oxit, phan img vdi nhieu chai oxi hoa khae nhu HNO3, H2SO4 dae, KCIO3,... 0 0 +4 Thidu : C + 4HN03(dac)—^ CO2 +4NO2 + 2H2O 0 o +2 C + ZnO -^-^ Zn + CO 2. Tinh oxi hoa a) Tdc dung vdi hidro O nhiet do cao va cd chat xuc tac, C tac dung vdi khi H2 tao thanh khi CH4 : 0 „ -4 C +2H2 ' •^' ) CH4 b) Tdc dung vdi kim loai 0 nhiet dg cao, C tac dung dugc vdi mgt so kim loai tao thanh cachua kim logi. 0 ,„ -4 . Thidu: 4A1 +3 C — ^ AI4C3 nhom cachua IV-UNG DUNG Kim cuang dugc dung lam dd trang sdc, che tao mui khoan, dao cat thuy tinh, lam bgt mai. Than chi dugc diing lam dien cue, lam ndi de na'u chay cac hgp kim chiu nhiet, che tao chai bdi tron. lam but chi den. Than coc dugc dung lam chai khd trong luyen kim, de luyen kim loai td quang. Than go duge dung de ehe tao thude nd den, thud'c phao, ... Loai than ed kha nang hap phu manh duge ggi la than hoat tinh. Than hoat tinh dugc dung trong mat na phdng ddc va trong cdng nghiep hoa chai. Than mugi dugc dung lam chai ddn cao su, de san xuat muc in, xi danh giay, ... 68 TRANG THA I T U NHIEN Trong tu nhien, kim cuong va than chi la cacbon tu do gan nhu tinh khiet. Ngoai ra, cacbon cdn cd trong eae khoang vat nhu can.xit (da vdi, da phan, da hoa deu chda CaCOj). magiezit (MgC03). dolomit (CaC03.MgC03) (hinh 3.2), ... va la thanh phan ehinh eua cac loai than md (than antraxit, than md, than nau, than bun, ehdng khae nhau ve tudi dia chai va ham lugng cacbon), dau md, khi thien nhien. Hgp chai cua cacbon la thanh phan co sd eua cae te bao ddng vat va thuc vat, nen cacbon cd vai trd rai ldn ddi vdi su sd'ng. Nude ta cd md than antraxit ldn d Quang Ninh, mdt sd md than nhd hon d Thanh Hoa, Nghe An, Quang Nam, ... a) Canxit b) Dolomit Hmh 3.2. Mgt sd khodng vat chua cacbon VI -OIEU CHE c) Magiezit Kim cuang nhdn tao duge dieu ehe td than chi, bang each nung than chi 0 khoang 2000 °C, dudi ap suat 50 den 100 nghin atmotphe vdi chai xuc tac la sat, erom hay niken. Than chi nhdn tao dugc dieu che' bang each nung than ede d 2500 - 3000 °C trong Id dien, khdng cd mat khdng khi. Than coc dugc dieu che bang each nung than md khoang 1000 °C trong Id cdc, khdng ed khdng khi. Than mo dugc khai thac true tiep td cae via than nam d cac dg sau khae nhau dudi mat dai. Than go duge tao nen khi ddi gd trong dieu kien thieu khdng khi. Than mugi dugc tao nen khi nhiet phan metan cd chai xuc tac : CH, t . xt ^ C + 2HT 69 BAI TAP 1. Tai sao hau het cac hgp chai cua cacbon lai la hgp chai cgng hoa tn ? 2. Tfnh oxi hoa cua cacbon the hien d phan dng nao trong cac phan dng sau ? A. C + O2 > CO2 B. C + 2CuO > 2Cu + CO2 C. 3C + 4AI > AI4C3 D. C + H2O > CO + H2 3. Tinh khd cua cacbon the hien d phan dng nao trong cac phan dng sau ? A. 2C + Ca > CaC2 B. C + 2H2 > CH4 C. C + CO2 > 2C0 D. 3C + 4AI > AI4C3 4. Lap phUdng trinh hoa hpe cua cac phan dng sau day : a) H2SO4 (dac) + C — ^ S02'+ CO2 + ? b) HNO3 (dac) + C > NO2 + CO2 + ? c) CaO + C — ^ CaC2 + CO d) Si02 + C — ^ Si + CO 5. Ddt mdt miu than da (chda tap chai khdng chay) cd khdi lugng 0,600 kg trong oxi dU, thu dupc 1,06 m^ (dktc) khf cacbonic. Tinh thanh phan phan trSm khdi lUdng cua cacbon trong mau than da tren. 70 HOP CHAT CUA CACBON & Biei tinh chat, dieu che, ung dung cua cac oxit cacbon va mudi cacbonat. A - CACBON MONOOXIT I - TiNH CHAT VAT Li Cacbon monooxit (CO) la chai khi khdng mau, khdng mui, khdng vi, hoi nhe hon khdng khi, rai it tan trong nudc, hoa ldng d -191,5 °C, hoa ran d -205,2 °C, rai ben vdi nhiet. Khi CO rat dgc. li - TiNH CHAT HOA HOC 1. Cacbon monooxit ia oxit khong tao muoi (oxit trung tinh) CO khdng tac dung vdi nudc, axit va dung dich kiem d dieu kien thudng. 2. Tinh khu Khi ddt ndng, khi CO chay trong oxi hoae trong khdng khi, cho nggn Ida mau lam nhat va toa nhieu nhiet : +2 ,0 +4 2 CO +O2 -^—> 2CO2 Vi vay, khi CO duge su dung lam nhien lieu khf. O nhiet do cao, khi CO khu dugc nhieu oxit kim loai. +2 +4 Thidu: Fe203-h3CO —i- ^ 2Fe+3C0 2 Tfnh chai nay dugc dung trong luyen kim de khu cac oxit kim loai. Ill -DIEU CHE 1. Trong phong thi nghiem Khf CO duge dieu che bang each dun ndng axit fomie (HCOOH) khi cd mat H2SO4 dac HCOOH ^250,6,0,^" ^ ^^^ ^ 2O 71 Trong cong nghiep Khf CO thudng dugc san xuai bang each cho hoi nudc di qua than nung dd : 4050 °C C + H^O ^ CO + H^ Hdn hgp khi tao thanh dugc ggi la khi than uat, chua trung binh khoang 44% CO, edn lai la cac khi khae nhu CO2, Hj, N,, ... Khi CO edn dugc san xuat trong cac Id gas (hinh 3.3) bang each thdi khdng khi qua than nung dd. O phan dudi cua Id, cacbon chay thanh cacbon dioxit. Khi di qua ldp than nung dd, CO2 bi khu thanh khi CO : CO2 + C 2C0 Hinh 3.3. So dd Id gas Hdn hgp khi thu duge ggi la khi Id gas (khi than kho). Trong khf Id gas, CO thudng chie'm khoang 25%, ngoai ra cdn cd Nj, COj va mdt lugng nhd eae khi khae. Khi than udt, khi Id gas deu dugc dung lam nhien lieu khi. B - CACBON DIOXIT I - TiNH CHAT VAT Li Cacbon dioxit (CO2) la chai khf khdng mau, nang gap 1,5 lan khdng khf, tan khdng nhieu trong nudc : C) dieu kien thudng, 1 ht nude hoa tan dugc 1 ht khi CO2. O nhiet do thudng, dudi ap suat 60 atm, khi CO2 se hoa thanh chat long khdng mau, linh dgng. Ci trang thai ran. COj tao thanh mdt khdi trdng, ggi la "nudc da khd". Nude da khd khdng ndng chay ma thang hoa , dugc dung de tao mdi trudng lanh khdng cd hoi am. CO2 la chai gay nen hieu dng nha kfnh, lam eho Trai Dat bi ndng len. II - TiNH CHAT HO A HOC Khi CO2 khdng chay va khdng duy tri su chay eua nhieu chai, nen ngudi ta thudng dung nhung binh tao khf CO2 de dap tat cac dam chay. 72 COj la o.xit axit, khi tan trong nude mdt lugng nhd COj ket hgp vdi nudc tao thanh dung dich axit cacbonic : CO2 (k) + H2O (/) ^=^ H2CO3 (dd) III -Oli u CHE 1. Trong phong thi nghiem CO2 duge dieu che bang each cho dung dich HCl tac dung vdi da vdi : CaCOj + 2HC1 > CO21 + CaCl, + H2O 2. Trong cong nghiep Khf CO2 dugc thu hdi tu qua trinh ddt chay hoan toan than de eung cap nang lugng cho cac qua trinh san xuat khae. Ngoai ra, khf CO2 edn dugc thu hdi td qua trinh chuyen hoa khf thien nhien, cae san pham dau md, ... ; qua trinh nung vdi; qua trinh len men rugu td dudng glucozo. C - AXIT CACBONIC VA MUOI CACBONAT I - AXIT CACBONIC Axit cacbonic (H2COJ) rat kem ben, chi tdn tai trong dung dich loang, de bi phan huy thanh CO2 va H2O. Trong dung dich, axit nay phan li hai nac, chu yeu — 7 7 — thanh cac ion H+ va HCO3 va ehi tao thanh mdt lugng rat nho CO3 : H2CO3 ( > H+ + HCO3 HCO3 ( > H++CO3" Axit cacbonic tao ra hai loai mudi : Mudi cacbonat chda ion C03~ (Na2C03, CaC03, ...) ; mudi hidrocacbonat chda ion HCO3 (NaHCOj, Ca(HC03)2,...). II - MUOI CACBONAT 1. Tinh chat a) Tinh tan Mudi cacbonat cua kim loai kiem, amoni va da sd cac mudi hidrocacbonat de tan trong nudc. Mudi cacbonat cua kim loai khae khdng tan trong nudc. 73 b) Tdc dung vdi axit Mud'i cacbonat, cung nhu mudi hidrocacbonat, tac dung de dang vdi dung dich axit, cho khi CO2 thoat ra. Thi du : NaHC03 + HCl > NaCl + CO2T + H2O HCO3 + H+ > CO2I' +H2O Na2C03 + 2HC1 > 2NaCl + C02t + H2O CO^" + 2H+ > C02t +H2O c) Tdc dung vdi dung dich kiem Cae mudi hidrocacbonat tac dung de dang vdi dung dich kiem. Thi du : NaHC03 + NaOH > NajCOj + H2O HCO3 + OH- > col' +H2O d) Phdn iing nhiet phdn Mudi cacbonat trung hoa cua kim loai kiem ben vdi nhiet. Mudi cacbonat trung hoa cua kim loai khae, cung nhu mudi hidrocacbonat, bi nhiet phdn buy. Thi du : MgC03 (r) — ^ MgO (r) + CO2 (k) 2NaHC03(r) — ^ Na2C03 (r) + CO2 (k) + H2O (k) 2. ling dung Canxi cacbonat (CaCOj) tinh khiet la chai bdt mau trang, nhe, dugc dung lam chat ddn trong mgt so nganh cdng nghiep. Natri cacbonat khan (Na2C03, cdn ggi la soda khan) dugc dung trong cdng nghiep thuy tinh, dd gdm, bgt giat, ... Natri hidrocacbonat (NaHC03) dugc dung trong cdng nghiep thuc pham. NaHCOj cdn dugc dung lam thud'c giam dau da day do thda axit. 74 BAI TAP 1. Lam the nao de loai hoi nudc va khf CO2 cd lan trong khi CO ? Viei cac phuong trinh hoa hgc. 2. Cd ba chai khf gom CO, HCl va SO2 dUng trong ba binh rieng biet. Trinh bay phuong phap hoa hpe de phan biet tung khi. Viet cac phUdng trinh hoa hoc. 3. Dieu nao sau day khong dung cho phan dng cua khf CO vdi khi O2 ? A. Phan dng thu nhiet. B. Phan dng toa nhiet. C. Phan dng kem theo sU giam the tich. D. Phan Ung khdng xay ra d dieu kien thudng. 4. a) Khi dun ndng dung djch canxi hidrocacbonat thi cd ket tua xuat hien. Tong cac he sd tl lugng trong phuong trinh hoa hpe ciia phan dng la A. 4 B. 5 C. 6 D. 7 b) Khi cho du khi CO2 vao dung dich chda ket tiia canxi cacbonat, thi ket tua se tan. Tong cac he sd tl lupng trong phuong trinh hoa hoc cija phan dng la A. 4 B.S C. 6 D. 7 5. Cho 224,0 ml khi CO2 (dktc) ha'p thu het trong 100,0 ml dung dich kali hidroxit 0,200M. Tinh khdi lugng cua nhdng chai cd trong dung djch tao thanh. 6. Nung 52,65 g CaC03 d 1000 °C va cho toan bg lUdng khi thoat ra hap thu hei vao 500,0 ml dung djch NaOH 1,800M. Hdi thu dugc nhdng mudi nao ? Khdi lUOng la bao nhieu ? Biet rang hieu suai cua phan dng nhiet phan CaC03 la 95 %. 75 SILIC VA HOP CHAT CUA SILIC & Biei nhung tinh chai dac trung cua silic va hap chai cua nd. & Biei nhung ung dung quan trong cua silic trong cac nganh ki thuat nhu luyen kim, ban din, dien tu, ... A - SILIC Silic d d thd 14, nhdm IV A, chu ki 3 cua bang tuan hoan. Cau hinh electron cua nguyen td silic la ls-2s-2p(>3s-3p-. ldp ngoai cung ed 4 electron, nen trong cac hgp chai, nguyen tu silic ed the tao dugc tdi da 4 lien ket cdng hoa tri vdi cae nguyen td khae. I - TiNH CHAT VAT Li Silic (Si) tdn tai d hai dang : silic tinh the' va silic vd dinh hinh. Silic tinh the cd eau true gid'ng kim cuong, mau xam, cd anh kim, cd tfnh ban dan, ndng chay d 1420 °C. Silic vd dinh hinh la chai bdt mau nau. II - TiNH CHAT HOA HOC Cung gidng nhu cacbon. silic ed eae so oxi hoa -4 , 0, +2 va +4 (so oxi hoa +2 ft dae trung ddi vdi silic). Trong cac phan dng oxi hoa - khd, silic the hien tinh khu hoae tinh oxi hoa. Silic vd dinh hinh boat dgng hon silic tinh th^. 1. Tinh khu a) Tdc dung vdi phi kim Silic tac dung true tiep vdi flo d dieu kien thudng ; vdi clo, brom, iot, oxi khi dun ndng : vdi cacbon, nito, luu huynh d nhiet do rai cao. Thidu : b) Tdc dung vdi hgp chdt 0 Si 0 Si + 2F2 + O2 V / } +4 SiF4 silic tetraflorua +4 SiOj silic dioxit Silic tac dung tuong ddi manh vdi dung dich kiem, giai phdng khf hidro : 0 +4 Si +2NaOH + H20 > Na2Si03 + 2H2T 76 2. Tinh oxi hoa 6 nhiet do cao, silic tac dung vdi cae kim loai nhu canxi, magie, sat, tao thanh silixua kim loai. 0 Thi du : 2Mg + Si -^-^ MgjSi magie silixua III - TRANG THAI T U NHIE N Silic la nguyen td phd bien thd hai, sau oxi, chiem gan 29,5% khdi lugng vd Trai Dai. Trong tu nhien khdng cd silic d trang thai tu do, ma chi gap d dang hgp chai : chu yeu la silic dioxit ; cac khoang vat silicat va aluminosilicat nhu cao lanh, mica, fenspat, da xa van, thach anh (hinh 3.4),... Hinh 3.4. Cdc tinh the thach anh IV - UNG DUNG Silic sieu tinh khiet la chai ban dSn, dugc di:mg trong ki thuat vg tuyen va dien tu, de' che tao te bao quang dien, bg khuech dai, bg ehinh luu, pin mat trdi, ... Trong luyen kim, silic dugc dung de tach oxi khdi kim loai ndng chay. Ferosilic la hgp kim dugc dung de che tao thep chiu axit. V-OIEU CHE Silic dugc dieu che bang each dung chai khd manh nhu magie, nhdm, cacbon khu silic dioxit d nhiet do cao. t° Thi dii : SiOj + 2Mg > Si + 2MgO 77 B - HOP CHAT CUA SILIC I - SILIC DIOXIT Silic dioxit (SiO^) la chai d dang tinh the, ndng chay d 1713 °C, khdng tan trong nudc. Silic dioxit tan cham trong dung dich kiem dac, ndng, tan de trong kiem ndng chay: Si02 + 2NaOH '° > Na2Si03+H20 Silic dioxit tan duge trong axit flohidric : Si02+4HF -> SiF4 + 2H2O Dua vao tinh chai nay, ngudi ta dung dung dich HF de khae ehu va hinh len thuy tinh. Trong tu nhien, silic dioxit tdn tai dudi dang cat va thach anh. Silic dioxit la nguyen lieu quan trgng de san xuat thuy tinh, dd gdm, ... II - AXITSILIXIC Axit silixic'-^^ (H2Si03) la chai d dang keo, khdng tan trong nudc, dl mai nudc khi dun ndng. Khi say khd, axit silixic mat mdt phan nudc. tao thanh vat lieu xd'p la silica gen (hinh 3.5). Do ed tdng dien tfch be mat rai ldn, silieagen cd kha nang hap phu manh, thudng dugc dung de hut hai am trong cac thung dung hang hoa. Axit silixic la axit rat ye'u, yeu hon ca axit cacbonic, nen de bi khf cacbon dioxit day ra khdi dung dich mudi silicat : Hinh 3.5. Silieagen Na^SiO.+COn H2O -^ Na,CO,+H,SiO,i III - MUOI SILICAT Axit silixic de tan trong dung dich kiem, tao thanh mudi silicat. Chi ed silicat kim loai kiem tan dugc trong nudc. Dung dich dam dae cua Na2Si03 va K2Si03 dugc ggi la thuy tinh long. Vai hoac gd tam thuy tinh long se khd bi chay. Thuy tinh long edn duge dung de ehe tao keo dan thuy tinh va sd. ' Axit silixic tdn tai d mot sd dang : H4Si04 (axit orthosilixic), HjSiOj (Axit metasilixic),. 78 """