NHNG BI TPHOHC C NHIU PHNG PHP GII1PHN MTMT S PHNG PHP GII TON HO HC 1.Phng php p dng s bo ton khi lng, s mol nguyn t C sTrong cc qu trnh ho hc th :Tng khi lng ca cc cht trc phn ng lun bng tng khi lng ca cc cht sau phn ng :(tr c phnng) (sauphnng)m m Tng s mol nguyn t ca nguyn t A trc phn ng lun bng tng s mol nguyn t ca nguyn t A sau phn ng. A(tr c phnng) A(sauphnng)n nCch p dngKhi gii bi tp trc nghim ta nn lp s tm tt cc phn ng, ri p dng nhng s bo ton trn tm ra cc i lng khc nh : s mol, khi lng cc cht trong s phn ng th bi ton s c gii nhanh hn. Bi tp minh haBi 1. Ngi ta cho t t lung kh CO i qua mt ng s ng 5,44 g hn hp A gm FeO, Fe3O4, Fe2O3, CuO nung nng, kt thc phn ng thu c hn hp cht rn B v hn hp kh C. Sc hn hp kh C vo dung dch nc vi trong d thy c 9 g kt ta v kh D bay ra. Khi lng cht rn B thu c lA. 3g B. 4gC. 5g D. 3,4g2Li giiS phn ng:FeOCO+ Fe2O3 ot A+CO2 Fe3O4CuOCO2+Ca(OH)2

CaCO3+H2O0,0990,09(mol)100 Theo nh lut BTKL th2CO A B COm m m m + +0,09.28+5,44=mB + 0,09.44 m = 4gBi 2.Cho mg hn hp A gm ba mui XCO3, YCO3v M2CO3tc dng vi dung dch H2SO4long, phn ng xy ra hon ton thu c 4,48 lt CO2 (ktc), dung dch B v cht rn C. C cn dung dch B thu c 20 g mui khan. Nung cht rn C n khi lng khng i thy c 11,2 lt kh CO2 (ktc) bay ra v cht rn D c khi lng 145,2 g. m c gi tr lA. 170g B. 180gC. 190g D. 200gLi giiXCO3YCO3 +H2SO4 mui B + CO2 + H2O +C M2CO3Nhit phn BC otD +CO22C D CO1,12m m m 145,2 .44 167,2(g)22,4 + + 3Phng trnh ion rt gn khi cho A tc dng vi H2SO423 2 2CO 2H CO H O4,480,4 0,2 0,222,4 ++ +

m +0,2.98=20+0,2.44+0,2.18 + 167,2 m = 180 gBi 3. Ha tan hon ton 3,22g hn hp X gm Fe, Mg, Zn bng mt lng va dung dch H2SO4 long, thu c V lt H2 (ktc) v dung dch cha m g hn hp mui Y. Cho ton b lng H2 trn i t t qua ng s ng 4 g hn hp gm Fe2O3, CuO nung nng, thu c 3,04g hn hp kim loi. m c gi tr l A. 8,98g B. 8,89gC. 7,89g D. 6,98gLi giiS (1) phn ng ca X tc dng vi H2SO4 long:2 4 2FeMg H SO Hnh p mui Y + HZn+ S (2) phn ng kh Fe2O3, CuO bi kh H2 :2 3Fe OCuO+ H2 FeCu +H2OBn cht cc phn ng xy ra theo s (2) l H2 + O(oxit) H2O2H O4 3,04n n 0,06(mol)16 Theo s (1) th mmui = 24XSOm m 3,22 0,06.96 8,98g+ + Bi 4. Nung nng m g hn hp X gm ACO3 v BCO3 thu c m g hn hp rn Y v 4,48 lt kh CO2. Nung nng Y n khi lng khng i thu thm 4c kh CO2 v hn hp rn Z. Cho ton b kh CO2 thu c khi nung Y qua dung dch NaOH d, sau cho dung dch BaCl2 d vo dung dch trn th thu c 19,7 g kt ta. Mt khc cho CO d qua hn hp Z nung nng thu c 18,4 g hn hp Q v 4,48 lt kh CO2 (ktc) . m c gi tr lA. 34,8 g B. 25,7gC. 44,1g D. 19,8gLi giiS phn ng nhit phn :33ACOBCO

Y +CO2(1) Y 0t Z +CO2 (2)2BaCl NaOH22 3 3CO CO BaCO19,70,1 0,1(mol)197 2CO Z Q CO + + (3)Bn cht ca s (3) l :CO +O(trong Z) CO2 m(trong Z) = 4,480,2(mol)22,4Z Q Om m m 18,4 0,2.16 21,6(gam) + + 2Y Z COm m m 21,6 0,1.44 26(gam) + + 2X Y COm m m 26 0,2.44 34,8(gam) + + Bi5.Ho tan hontonhnhpgm 0,2mol FeO, 0,3molFe2O3, 0,4 mol Fe3O4 vo dung dch HNO3 2M va , thu c dung dch mui v 5,6 lt 5kh hn hp kh NO v N2O4(ktc) c t khi so vi H2l 33,6. Th tch dung dch HNO3 tham gia phn ng lA. 3,6 lt B. 2,4 ltC. 3,2 lt D. 4,8 ltLi giiS phn ng : ot2 3 3 3 33 4FeOFe O HNO Fe(NO )Fe O+ + 2 4NON O + H2Ot2 4NO N On x(mol) ; n y(mol) 5,6x+y =0,25x 0,1mol 22,4Ta c h30x 92y y 0,15mol33,62(x y) ' '+ +p dng s bo ton nguyn t Fe tnh s mol Fe(NO3)3: 3 3 2 3 3 43 3 2 3 3 4Fe(Fe(NO ) Fe(FeO,Fe O ,Fe O )Fe(NO ) FeO Fe O Fe On nn n 2n 3n 0,2 2.0,3 3.0,4 2mol + + + + p dng s bo ton nguyn t N :3 3 3 2 4 3N(HNO ) N(Fe(NO ) NO N O ) HNOn n n 3.2 0,1 2.0,15 6,4mol+ + + + Vy 3HNO6,4V 3,2lt2 Bi 6.Ha tan hon ton hn hp gm 0,12 mol FeS2v a mol Cu2S vo dung dch HNO3 (va ), thu c dung dch X (ch cha 2 mui sunfat) v mt kh duy nht l NO. Gi tr ca a lA. 0,12 mol B. 0,04 mol C. 0,075 mol D. 0,06 molLi gii6S phn ng : 22FeSCu S+ HNO3 2 4 34Fe (SO )CuSO + NO+ H2O p dng nh lut bo ton nguyn t Fe, Cu, S FeS2 Fe2(SO4)30,12 0,06Cu2S CuSO4 a2a2 2 2 4 3 4S(FeS ) S(Cu S) S(Fe (SO ) ) S(CuSO )n n n n + +2 2 2 4 3 4FeS Cu S Fe (SO ) CuSO2n n 3n n + + 2.0,12 + a = 3.0,06 + 2a a = 0,06 molBi 7. Thi t t hn hp kh X gm CO v H2 i qua ng ng 16,8 g hn hp Y gm 3 oxit gm CuO, Fe3O4, Al2O3 nung nng. Sau khi phn ng hon ton thu c m g cht rn Z v mt hn hp kh T, hn hp T nng hn hn hp X l 0,32 g. Gi tr ca m lA. 14,28gB. 16,46gC. 16,48g D. 17,12gLi giiS phn ng2 32 3CuOFe OAl O +2COH Z + TTa thy X + O(oxit) TT X O(oxit)m m m 0,32g m Y Z Om m m +Z Y Om m m 16,8 0,32 16,48g 7Bi 8. Kh hon ton m g hn hp CuO, Fe3O4 bng kh CO nhit cao, thu c hn hp kim loi v kh CO2. Sc kh CO2 vo dung dch Ca(OH)2 thu c 20 g kt ta v dung dch A, lc b kt ta, cho Ba(OH)2 d vo dung dch A thu c 89,1 g kt ta na. Nu dng H2kh hon ton m g hn hp trn th cn bao nhiu lt kh H2 (ktc) ?A. 16,46 lt B. 19,72 ltC. 17,92 lt D. 16,45 ltLi giiS phn ng :3 4CuOFe O +COotCuFe+CO2(1)Cho CO2 vo dung dch Ca(OH)2 th223Ca(OH)2Ba(OH)3 2 3 320CaCO 0,2(mol)100CO (2)Ca(HCO ) CaCO BaCOx x + Z]100x 197x 89,1 x 0,3(mol) + p dng s bo ton nguyn t C2 3 32 3 3C(CO) C(CO ) C(CaCO ) C(BaCO )CO CaCO BaCOn n n nn n n (0,2 0,3) 0,3 0,8(mol) + + + + Bn cht cc phn ng xy ra trong (1) l :CO+O(oxit) CO2 0,8 0,80,8Nu dng H2 kh m g hn hp CuO, Fe3O4 th bn cht cc phn ng l 8H2+O(oxit) H2OTng s mol nguyn t oxi trong hai qu trnh ny bng nhau nn2 2H O H (ktc)n n 0,8(mol) V 0,8.22,4 17,92(lit) Bi tp vn dngBi 1. kh hon ton 27,2 g hn hp gm Fe, FeO, Fe3O4 v Fe2O3 cn va 6,72 lt CO (ktc). Khi lng Fe thu c lA. 18,9 gB. 22,4 g C. 19,8 gD. 16,8 gHng dn S phn ng 3 42 3FeFeOFe OFe O +COFe + CO2Bn cht cc phn ng xy ra trong s trn ch l : CO + O(oxit) CO2nCO = nO = 6,7222,4 = 0,1 (mol) mFe = mhh mO (oxit) = 27,2 16.0,3 = 22,4 g.Bi 2. Cho t t mt lung kh CO i qua ng s ng m g hn hp gm Fe, FeO, Fe3O4, Fe2O3 nung nng, kt thc phn ng thu c 64g st, kh i ra gm CO v CO2 cho sc qua dung dch Ca(OH)2 d c 40g kt ta. Vy m c gi tr l A. 70,4g B. 74gC. 47g D. 104gHng dn9Kh i ra sau phn ng gm CO2 v CO d cho i qua dung dch Ca(OH)2 d :CO2 + Ca(OH)2 CaCO3+ H2O0,4 (mol) 4 , 010040(mol)S phn ng:FeO CO + Fe2O3

Fe+CO2 Fe3O428.0,4+m=64 +44.0,4 m = 70,4gBi 3. Kh hon ton 24 g hn hp CuO v FexOy bng H2 d nhit cao thu c 17,6 g hn hp hai kim loi. Khi lng nc to thnh lA. 3,6 gB. 7,2 g C. 1,8 gD. 5,4 gBi 4. tc dng ht 5,44 g hn hp CuO, FeO, Fe2O3 v Fe3O4 cn dng va 90ml dung dch HCl 1M. Mt khc, nu kh hon ton 5,44 g hn hp trn bng kh CO nhit cao th khi lng st thu c lA. 3,20gB. 4,72 g C. 2,11 g D. 3,08 gBi 5. Thi rt chm 2,24 lt (ktc) hn hp X gm CO v H2 (ly d) qua ng s ng 24 g hn hp Al2O3, CuO, Fe2O3 v Fe3O4 un nng. Sau khi kt thc phn ng, khi lng cht rn cn li trong ng s lA. 12,4 gB. 14,2 gC. 22,8 gD. 22,4 gHng dn102 32 33 4Al OCuOFe OFe O+ 2COH Cht rn+ 22COH OTa thy 1 mol CO hoc 1 mol H2 u phn ng vi 1mol O :2COH+ O(oxit) 22COH O0,1 0,1Khi lng cht rn cn li l 24 0,1.16 =22,4 g Bi 6.Cho hn hp gm : FeO (0,01 mol), Fe2O3(0,02 mol), Fe3O4(0,03 mol) tan va ht trong dung dch HNO3thu c dung dch cha mt mui v 0,448 lt kh N2O4 (ktc). Khi lng mui v s mol HNO3 tham gia phn ng lA. 32,8 g ; 0,4 mol B. 33,88 g ; 0,46 molC. 33,88 g ; 0,06 mol D. 33,28 g ; 0,46 molHng dnS phn ng :FeOFe2O3+ HNO3Fe(NO3)3+N2O4+H2OFe3O4p dng s bo ton nguyn t Fe : 3 3 2 3 3 4Fe[Fe(NO ) ] Fe[FeO,Fe O ,Fe O ]n n 3 3Fe[Fe(NO ) ]n=2 3 3 4FeO Fe O Fe On 2n 3n + += 0,01 2.0,02 3.0,03 0,14(mol) + + 3 3Fe(NO )m 0,14.242 33,88(g) p dng s bo ton nguyn t N :113 3 3 2 43 3 3 2 4N[HNO ] N[Fe(NO ) N O ]HNO Fe(NO ) N On nn 3n 2n 3.0,14 2.0,02 0,46(mol)+ + + Bi 7.Cho 1,1 g hn hp Fe, Al phn ng vi dung dch HCl thu c dung dch X, cht rn Y v kh Z, ho tan ht Y cn s mol H2SO4 (long) bng 2 ln s mol HCl trn, thu c dung dch T v kh Z. Tng th tch kh Z (ktc) sinh ra trong c hai phn ng trn l 0,896 lt. Tng khi lng mui sinh ra trong hai trng hp trn lA. 2,92 g B. 2,67 gC. 3,36 g D. 1,06 gHng dnS phn ng :FeAl + 2 4HClH SO hn hp mui (X+T) + H2

t nHCl = x mol ; 2 4H SOn= y molp dng s bo ton nguyn t H :2 4 22 4 2H(HCl H SO ) H(H )HCl H SO Hn nn 2n 2n 0,04mol++ x + 2y = 0,04 y =2x x = 0,008 ; y = 0,016mmui = m(Al,Fe) + 2Cl SO4m m += 1,1 + 0,008.35,5 + 0,016.96 = 2,92 (g)Bi 8. Cho 2,48 g hn hp 3 kim loi Fe, Al, Zn phn ng va ht vi dung dch H2SO4 long thu c 0,784 lt kh H2 (ktc). C cn dung dch, khi lng mui khan thu c l A. 4,84 g B. 5,84 gC. 5,48 g D. 4,56 gHng dnS phn ng :12Fe FeSO4Al +H2SO4 Al2(SO4)3+H2Zn ZnSO4p dng s bo ton nguyn t H: n 2 4H SO = n 2H= 0, 78422, 4 = 0,035 (mol)p dng s bo ton nguyn t S: 2 24 2 4 4SO (H SO ) SO (mui)n n = 0,035 (mol)mmui = m(Fe, Al, Zn) + 24SOm = 2,48 + 0,035.96 = 5,84 (g)Bi9.Hotan2,57ghp kimCu,Mg,Albngmt lng va dung dch H2SO4 long thu c 1,456 lt kh X (ktc), 1,28g cht rn Y v dung dch Z. C cn dung dch Z thu c m g mui khan, m c gi tr lA. 7,53g B. 3,25gC. 5,79g D. 5,58g Hng dnCch gii tng t bi 8S phn ng :CuMgAl'+H2SO4

42 4 3MgSOAl (SO )+ Cu+H2Cu khng tc dng vi HNO3 long nn 1,28 gam cht rn Y l Cu.+ + + 24(Al Mg)SOm m m (2,57 1,28) 0,065.96 7,53(g)Bi 10. Cho 17,5 g hn hp gm 3 kim loi Fe, Al, Zn tan hon ton trong dung dch H2SO4 long thu c 5,6 lt kh H2 ( 0oC, 2 atm). C cn dung dch, khi lng mui khan thu c lA. 65,5 g B. 55,5 g13C. 56,5 g D. 55,6gHng dn 2H2.5,6n 0,5(mol)0,082.273 ZnFeAl' + H2SO4 dung dch 3 mui + H224(Al,Zn,Fe)SOm m m += 17,5+0,5.98=65,5 (g)Bi 11. Cho 35g hn hp Na2CO3, K2CO3 tc dng va ht vi dung dch BaCl2. Sau phn ng thu c 59,1g kt ta. Lc tch kt ta, c cn dung dch thu c m g mui clorua. Vy m c gi tr lA. 38,3g B. 22,6g C. 26,6g D. 6,26gHng dnS phn ng: 2 32 3Na COK CO +BaCl2

BaCO3 + NaClKCl 2 3BaCl BaCOn n 0,3(mol)p dng nh lut bo ton khi lng:+ +2hh BaClm m m mm = 35 + 0,3.208 59,1 = 38,3 (g)Bi 12.Cho 4,48g hn hpcht rn Na2SO4, K2SO4, (NH4)2SO4tan vo nc c dung dch A. Cho A tc dng va vi 300 ml dung dch Ba(NO3)2 0,1M. Kt thc phn ng thu c kt ta B v dung dch C. Lc tch kt ta, c cn dung dch C thu c m(g) mui nitrat. Vy m c gi tr lA. 5,32g B. 5,23g C. 5,26g D. 6,25gHng dn14S phn ng:Na2SO4NaNO3K2SO4+ Ba(NO3)2 BaSO4+ KNO3(NH4)2SO4NH4NO3 3 2 4Ba(NO ) BaSOn n 0,03(mol)C C4,48 7,83 6,99 m m 5,32(g) + + Bi 13. Ho tan hon ton 3,72g hn hp 2 kim loi A, B trong dung dch HCl d thy to ra 1,344 lt kh H2 (ktc). C cn dung dch sau phn ng thu c mui khan c khi lng lA. 7,12gB. 7,98gC. 3,42g D. 6,12gHng dnS phn ng :AB+ HCl

nmAClBCl+H2+ H Cl1,344n n 2. 0,12(mol)22,4mmui = mKL + Clm= 3,72 + 0,12.35,5 = 7,98 (g)Bi 14. Nung m g hn hp A gm 2 mui MgCO3 v CaCO3 cho n khi khng cn kh thot ra thu c 3,52g cht rn B v kh C. Cho ton b kh C hp th ht bi 2 lt dung dch Ba(OH)2 thu c 7,88g kt ta. un nng dung dch li thy to thnh thm 3,94g kt ta na. Cc phn ng xy ra hon ton, m c gi tr lA. 7,44g B. 7,40gC. 7,04g D. 4,74gHng dnm = mB + 2COm 15CO2 + Ba(OH)2 BaCO3 + H2O2CO2 + Ba(OH)2 Ba(HCO3)2 Ba(HCO3)2 BaCO3+ CO2+ H2Om = 3,52 + (7,88 3, 942. ).44 7, 04197 197+ (g) Bi 15. Cho hn hp A gm 0,1 mol Cu, 0,2 mol Ag phn ng ht vi V lt dung dch HNO3 1M thu c dung dch X v hn hp Y gm 2 kh NO, NO2 (2NO NOn n 0,1mol ). V c gi tr lA. 1 lt B. 0,6 ltC. 1,5 lt D. 2 ltHng dnS phn ng:CuAg+ HNO33 23Cu(NO )AgNO+2NONO +H2Op dng s bo ton nguyn t Cu, Ag ta c :nCu = 3 2Cu(NO )n= 0,1 molvnAg = n3AgNO= 0,2 molp dng cho nguyn t N : 3N (HNO )n = 3 2 3 2N(Cu(NO ) AgNO NO NO )n+ + + 3(HNO )n= 3 2 3 2Cu(NO ) AgNO NO NO2n n n n + + + 3(HNO )n = 2.0,1 + 0,2 + 0,1 + 0,1 = 0,6 mol3HNO0,6V 0,6(lit)1 Bi 16. A, B l 2 kim loi thuc nhm IIA. Ha tan hon ton 10,94 g hn hp X gm 2 mui clorua ca A v B vo nc c 100 g dung dch Y. kt ta ht ion Cl- c trong 50 g dung dch Y phi dng dung dch c cha 10,2 16g AgNO3. Nu cho Y tc dng vi dung dch H2SO4 d (gi thit ASO4 v BSO4 u kt ta), th thu khi lng kt ta thu c l A: 12,44 B: 13,44C: 14,33 D: 13,23Hng dn ACl2+AgNO3 AgCl + ... BCl2Trong 50 g dung dch Y :AgClCl Agn n n 0,06(mol) + Trong 100 g dung dch Y : (A,B)Cln 0,12(mol) m 10,94 0,12.35,5 6,68g S mol in tch 24Cl SO2n n m = 6,68 + 0,06.96 = 12,44 gBi 17. t chy m g mt hirocacbon A vi 11,76 lt O2 (ktc) va . Phn ng to ra 8,1 g nc v mt lng CO2. Cng thc phn t ca A lA. C2H6B. C2H4C. C3H6D. C2H8Hng dnx y 2 2 2C H O CO H O + +p dng s bo ton nguyn t O : + + 2 2 2 2 2 2 2O(O ) O(CO ) O(H O) O CO H O COn n n 2n 2n n n 0,3(mol) C Hn 0,3(mol) ; n 0,9(mol) CTGN l CH3, CTPT l (CH3)n + 2 63n 2n 2 n 2chn n=2 CTPTC HBi 18. t chy m g hp cht A (CnHn1ONa) vi mt lng va l 6,272 lt O2 (ktc) thu c 2,12 g Na2CO3 v hn hp X cha CO2, H2O. Nu cho 17hn hp X qua bnh ng H2SO4 c th khi lng bnh tng 1,8 g. Vy m c gi tr lA. 6,46 B. 4,64C. 4,46 D. 6,44Hng dnCnHn1ONa 2O +Na2CO3 + CO2 + H2O2 3 2 3Na(A) Na(Na CO ) Na COn n 2n 2.0,02 0,04(mol) 2 2 3 2 22 2O(A) (O ) Na CO CO H OCO COn 2n 3n 2n n2n 2.0,28 0,04 3.0,02 0,1 0,44(mol) n 0,22(mol)+ + + + Am 12(0,02 0,22) 0,1.2 0,04.(16 23) 4,64(g) + + + + Bi 19. Thu phn hon ton 1 este n chc A cn va 100ml NaOH 1M thu cancol etylic v mui ca axit hu c B. Phn hu hon ton B thu c 5,6 lt kh CO2 (ktc), 4,5 g H2O v m g Na2CO3. Cng thc cu to ca A lA. C2H5COOC2H5B. CH3COOC3H7C. C3H7COOC2H5D. C3H7COOCH3Hng dnS phn ng :2 52 2 2 3A NaOH C H OH BB CO H O Na CO+ + + +2 5A NaOH C H OH Bn n n n = 0,1 (mol).2 5 2 2 32 5 2 2 3C(A) C(C H OH) C(CO ) C(Na CO )C H OH CO Na COn n n n2n n n 2.0,1 0,25 0,05 0,5(mol) + + + + + + S nguyn t C trong A l0,550,1 (nguyn t).182 5 22 5 2H(A) H(C H OH) H(H O) H(NaOH)H(A) C H OH H O NaOHn n n nn 6n 2n n 6.0,1 2.0,25 0,1 1(mol) + + + S nguyn t H trong A l 1100,1 (nguyn t)CTPT A. C5H10O2 CTCT A C2H5COOC2H5Bi 20. t chy hon ton m(g) hn hp X gm C2H2, C3H6 v C4H10 thu c 2,688 lt kh CO2 (ktc) v 2,16 g H2O. Vy m c gi tr lA. 1,48gB. 2,86 g C. 14,8gD. 1,68g Hng dnX C H2,688 2,16m m m .12 .2 1,68(g)22,4 18 + + Bi 21. Cho 13,8g hn hp gm ancol etylic v glixerol tc dng va vi Na thu c 4,48 lt H2 (ktc) v dung dch mui. C cn dung dch mui, khi lng cht rn thu c lA. 22,6 gB. 22,4 g C. 34,2 gD. 25,0 gHng dnp n A (m mui = 22,6 g)Bi23.tchyhontonhp cht A c CTPT n 2n 1C H COONavi oxi thu c 21,2g Na2CO3, 10,8g H2O v mt lng CO2. Lng CO2 ny cho tc dng vi dung dch Ca(OH)2 d thu c 100 g kt ta. Cng thc phn t A l2 5 32 3 3 7A. C H COONa B. CH COONaC. C H COONa D. C H COONaHng dn

n 2n 1 2 2 3 2 2C H COONa+ ONa CO + CO + H O193 2A Na CO H H O210,8n 2n 2.0,2 0,4(mol) ; n 2.n 2. 1,2(mol)18 2 33 2CO CaCOC(A) C(CaCO ) C(CO )n n 1 (mol)n n n 0,2 1 1,2(mol) + + 2 2 3 2CO Ca(OH) CaCO H O + +O(A) A Na(A) An 2n 0,8(mol) ; n n 0,4(mol) + + + + + + + A C H O NaA 2 3m m m m m 1,2.12 1,2 0,8.16 0,4.23 37,6 (g)37,6M 94 14n 66 94 n 2 CTPTA: C H COONa0,4Bi24.un13,8 g hn hp 3ancol no,n chc vi H2SO4c 1400C thu c 11,1g hn hp cc ete c s mol bng nhau. Tnh s mol mi ete.A. 0,025 mol B. 0,1molC. 0,15 mol D. 0,2 molHng dnun hn hp 3 ancol c 3.(3 1)62+ ete.Theo nh lut bo ton khi lng: mancol = mete + 2H Om2H Om = mancol mete = 13,8 11,1 = 2,7 (g)Tng s mol cc ete = s mol H2O = 2,718 = 0,15 (mol)S mol mi ete = 0,150,0256 (mol) Bi 25.t chy hon ton mt cht hu c A cha 1 nguyn t Oxi thu c hn hp sn phm B. Cho B i qua dung dch Ca(OH)2 d thy c 15 g kt ta v khi lng dung dch gim 4,8 g. CTPT ca A lA : CH4O B : C2H6O20C : C3H8O D : C4H10O Hng dnTheo L bo ton khi lng th :mdung dch u + 2 2CO H O ddsaum m m m + +Nu khi lng dung dch tng th : mdung dch tng = mdung dch sau mdung dch u = 2 2CO H O(m m ) m + Nu khi lng dung dch gim th mdung dch gim = mdung dch u mdung dch sau = 2 2CO H Om (m m ) +CO2 + Ca(OH)2 CaCO3 + H2O 4,8 = 0,15.100 0,15.44 2 2H O H Om m 3,6(gam) CnH2n+2O nCO2 + (n+1)H2O0,15 0,20,2n = 0,15(n+1) n =3 CTPTC3H8OBi 26. Hn hp X gm 0,1 mol 2 4 2C H Ov 0,2 mol hirocacbon A. t chy ht X cn 21,28 lt O2 (ktc) v ch thu c 35,2 g CO2 v 19,8 g H2O. Cng thc phn t khi ca A lA. 7 8C HB. 8 8C H C. 6 6C HD. 8 6C HHng dn2 2 2X O CO H O + +2 4 2 2 2 2A C H O O CO H Om m m m m + + +A21,28m (35,2 19,8) ( .32 0,1.62) 18,4g22,4 + + 21A18,4M 920,2 g/mol 12x y 92 + Vy gi tr ph hp x = 7 ; y = 8 7 8CTPT C H Bi 28.Nhit phn 8,8 g C3H8 thu c hn hp kh A theo phng trnh phn ng:C3H8 CH4+C2H4C3H8 C3H6+H2t hon ton A khi lng CO2 v H2O to thnh lA. 24,6 g; 14,4 g B. 26,4 g; 16,4 gC. 23,5 g ; 15,5 g D. 32,5 g ; 14,8 gHng dnTheo nh lut bo ton khi lng th :3 8C H Am m t chy cht A cng chnh l t chy 3 8C Hhoc t chy C v H :C+O2 CO20,60,6 0,6H2 + 12O2 H2O0,8 0,40,8 222OCOH OV 22,4ltm 0,6.44 26,4(g)m 0,8.18 14,4(g)222.Phng php tng gim khi lngC sKhi mt nguyn t hay nhm nguyn t X trong cht tham gia phn ng (gi l cht u) c thay th bng mt nguyn t hay nhm nguyn t Y to ra cht mi (cht cui), th s chnh lch khi lng gia cht u v cht cui chnh bng hiu khi lng ca hai nhm nguyn t X v Y (|XY|). Th d : CaCO3 CaSO4 Ta thy th s chnh lch khi lng gia hai mui CaCO3v CaSO4 : M (40 96) (40 60) 36g/ mol + + ngbngschnhlchkhi lng ca hai anion 23CO (60g)v 24SO (96 g):M 96 60 36g/ mol .Cch p dngKhi mt cht thay anion c bng anion mi sinh ra cht mi th s chnh lch khi lng gia cht c v cht mi chnh l s chnh lch khi lng ca anion c v anion mi.Khimt cht thaycationcbngcationmi sinhracht mi ths chnh lch khi lng gia cht c v cht mi chnh l s chnh lch khi lng ca cation c v cation mi.Bi tp minh hoBi 1. Cho 41,2 g hn hp X gm Na2CO3, K2CO3 v mui cacbonat ca kim loi ho tr 2 tc dng vi dung dch H2SO4 d. Kt thc phn ng thu c hn hp Y gm ba mui sunfat v 8,96 lt kh CO2 (ktc). Khi lng ca Y lA. 58,6 g B. 55,6 gC. 45,0 gD. 48,5 g Li giiS phn ng :232 32 33Na COK COMCO +H2SO4

2 42 44Na SOK SOMSO+H2O+ CO21 mol X chuyn thnh 1 mol Y th tng khi lng l M 96 60 36(g/ mol) Theonhlut botonnguyntC:223COCOn n 0,4(mol) khi lng Y ln hn khi lng ca X l 0,4.36 = 14,4 (g)Vy mY = 41,2 + 14,4=55,6 (g)Bi 2.Cho 84,6 g hn hp A gm BaCl2v CaCl2 vo 1 lt hn hp Na2CO3 0,3Mv (NH4)2CO30,8 M.Sau khi cc phn ng kt thc ta thu c 79,1 g kt ta A v dung dch B. Phn trm khi lng BaCl2v CaCl2 trong A ln lt lA. 70,15% ; 29,25% B. 60,25% ; 39,75%C. 73,75%; 26,25% D. 75,50% ; 24,50%Li giit 2 2BaCl CaCln x(mol); n y(mol) 22BaClCaCl+2 34 2 3Na CO(NH ) CO

33BaCOCaCO + 4NaClNH ClC 2 mol Cl mt i (71 g) c 1 mol mui 23COthm vo (60 g) chnh lch (gim) khi lng ca 1 mol mui lM = 71 60 =11(g) gim khi lng mui :m = 84,6 79,1 = 5,5 (g)Vy s mol mui clorua bng s mol mui cacbonat phn ng =5,50,5(mol)11 M s mol CO32(theo gi thit) = 0,3 + 0,8 = 1,1 (mol) > 0,5 mol (phn ng). Vy mui cacbonat phn ng d. 24x+y=0,5 (1)208x+ 111y= 84,6 (2)' x 0,3moly 0,2mol '

' 22BaClCaCl0,3.208%m .100% 73,75%84.6%m 100 73,75 26,25%Bi 3. Nhng mt thanh nhm nng 50g vo 200ml dung dch CuSO4 0,5M. Sau mt thi gian ly thanh nhm ra cn nng 51,38g. Gi s kim loi thot ra u bm c vo thanh nhm. Khi lng Cu thot ra lA. 0,64gB. 1,28g C. 1,92g D. 2,56gLi gii 2Al + 3Cu2+ 2Al3++3Cu2 mol (tan ra)3 mol Cu (bm vo)Th khi lng thanh kim loi tng l3.64 2.27 = 138 (g)ng vi khi lng tng 51,38 50 = 1,38g s mol Cu = 3.1,38138= 0,03 (mol)Theo gi thit s mol Cu2+ = 0,1 mol> 0,03 mol mCu = 0,03.64 = 1,92 (g)Bi 4. Ly mt inh st nng 20g nhng vo dung dch CuSO4 bo ha. Sau mt thi gian ly inh st ra sy kh, cn nng 20,4g. Khi lng Cu bm trn inh st lA. 0,4884 gB. 3,4188 g C. 3,9072 gD. 0,9768 gLi gii Fe + CuSO4 FeSO4 + Cu tng khi lng khi chuyn 1 mol Fe thnh 1 mol Cu l 64 56 = 8g tng khi lng thc lm = 20,4 20 = 0,4 g Cu0,4n 0,05mol8 25Khi lng Cu = 0,05.64 = 3,2 gBi 5. Ho tan 10g hn hp 2 mui ACO3 v B2(CO3)3 bng dung dch HCl ta thu c dung dch A v 0,672 lt kh bay ra ktc. C cn dung dch A th thu c m(g) mui khan. Vy m c gi tr lA. 1,033g B. 10,33gC. 9,265g D. 92,65gLi gii 32 3ACOB CO + HCl23AClBCl + CO2+H2OC 1 mol mui 23CO i ra (mt i 60g) c 2 mol Cl kt hp (thm 71g) chnh lch (tng) khi lng ca 1 mol mui l M = 71 60 =11 (g)m:223COCO0,672n n 0,03(mol)22,4 Vy khi lng mui tng :m = 11.0,03 = 0,33 (g) Tng khi lng mui clorua = 10 + 0,33 = 10,33 (g)Bi 6. Nung m g hn hp X gm hai mui cacbonat ca hai kim loi nhm IIA. Sau mt thi gian thu c 2,24 lt kh v cht rn Y. Ha tan Y vo dung dch HCl d thu c thm 4,48 lt kh v dung dch Z. C cn dung dch Z thu c 33 g mui khan (cc th tch kh o ktc). Gi tr ca m lA. 35,3 g B. 29,7 gC. 23,6 g D. 37,9 gLi giiGi cng thc chung ca X l 3MCOot3 2MCO MO CO +Ho tan Y (3MCOv MO) vo dung dch HCl26oo2t3 2 2 2t2 2COMCO 2HCl MCl H O COMO 2HCl MCl H On 0,2 0,1 0,3(mol)+ + ++ + + Khi1 mol mui 23CO chuyn thnh muiCl thM = 2.35,5 60 = 11gVi 0,3 mol mui23COth khi lng mui clorua nng hn khi lng mui 23CO l m 11.0,3 0,33(gam) Khi lng 3MCOM 33 0,33 29,7(gam) Bi 7. Hn hp A gm 10 g MgCO3, CaCO3 v BaCO3 c ho tan bng HCl d thu c dung dch B v kh C. C cn dung dch B c 14,4 g mui khan. Sc kh C vo dung dch c cha 0,3 mol Ca(OH)2 thu c s g kt ta lA. 10g B. 20gC. 30g D. 40gLi giiCO32+2H+ CO2 + H2Op dng phng php tng gim khi lng khi chuyn 23CO thnh Cl ta tnh c s mol A = 223COCO14,4 10n n 0,4(mol)11CO2 + Ca(OH)2

CaCO3 + H2O 0,40,30,3 CO2 + H2O + CaCO3 Ca(HCO3)2 0,10,13CaCOm 0,2.100 20g Bi8.Cho 68g hn hp 2 mui CuSO4v MgSO4tc dng vi 1lt dung dch cha KOH 1M v NaOH 0,4M. Sau phn ng thu c 37g kt ta v dung 27dch B. Vy phn trm khi lng CuSO4 v MgSO4 trong hn hp ban u ln lt lA, 47,50% ; 52,95%.B. 47,05 % ; 52,95%.C. 47,05% ; 53,59%.D. 47,50% ; 53,59%.Li giit 4 4CuSO MgSOn x(mol);n y(mol) 44CuSOMgSO +NaOHKOH 22Cu(OH)Mg(OH)+2 42 4Na SOK SOT chnh lch khi lng ca mui sunfat v khi lng kt ta trn ta tnh c tng s mol hai mui sunfat l 68- 37 =0,596- 34 (mol)x+ y =0,5 (1)160x+ 120y= 68(2)'x 0,2y 0,3 ' ' 44CuSOMgSO0,2.160%m .100% 47,05%68%m 100 47,05 52,95%Bi 9.Nhng mt thanh kim loi A (ho tr II) vo dung dch CuSO4. Sau phn ng khi lng thanh kim loi A gim 0,12g. Mt khc cng thanh kim loi AcnhngvodungdchAgNO3dth kt thcphnngkhi lng thanh tng 0,26g. Bit s mol A tham gia hai phn ng bng nhau. Kim loi A lA. Zn B. Mg C. Cd D. Fe Li gii Phng trnh phn ng :A + Cu2+ d A2+ + Cua aA + 2Ag+ d A2+ + 2Ag28 a2aKhi lng thanh kim loi tng=mA mCu = 0,12ga.MA 64a = 0,12 MA.a = 64a + 0,12 (1)Mt khc khi lng thanh kim loi gim=mAg + mA = 0,26 g2a.108 MA.a = 0,26 MA.a = 2a.108 0,26(2) x = 2,5.103 mol MA = 3364.2,5.10 0,12112(g/ mol)2,5.10+ Cht X l Cd. Bi 10. C 2 dung dch FeCl2 v CuSO4 c cng nng mol. Nhng thanh kim loi vo M (nhm IIA) vo V lt dung dch FeCl2, kt thc phn ng khi lng thanh kim loi tng 16g. Nhng cng thanh kim loi y vo V lt dung dch CuSO4 kt thc phn ng khi lng thanh kim tng 20g. Gi thit cc phn ng xy ra hon ton v kim loi thot ra bm ht vo M. Kim loi M l A. ZnB. Mg C. CdD. Fe Li gii Cc phng trnh phn ng xy ra :M +Fe2+ M2+ +Fex x xM +Cu2+ M2+

+Cu x x xTheo gi thit cc phn ng u xy ra hon ton nn cc ion 2 2Fe vCu+ + phn ng ht2 2Fe Cun n x(mol)+ + Khi lng thanh kim loi tng (1) l : m = mFe mM= 16g 56x MM.x = 16 M.x= 56x 1629Khi lng thanh kim loi tng (2) l : m = mCu mM= 20 g64x M.x = 20 M.x = 64x 20M = 24. Vy kim loi M l Mg.Bi tp vn dngBi 1. Cho 20 g hn hp X gm hai axit cacboxylic no, n chc tc dng va vi dung dch Na2CO3 thu c V lt kh CO2 (ktc) v dung dch mui. C cn dung dch thu c 28,8 g mui. Gi tr ca V lA. 3,36 lt B. 4,48 ltC. 2,24 lt D. 6,72 ltHng dnt cng thc chungca hai axit cacboxylic l n 2n 1C H COOH+2 3 2 22RCOOH Na CO 2RCOONa H O CO + + +C 1 mol hn hp axit hn hp mui th (tng)M = 22 g/molx mol

(tng)m = 28,8 20 = 8,8 gx = 8,822= 0,4 (mol) 2COn 0,2(mol) V 4,48lt Bi 2. Cho 4,16 g hn hp 2 axit cacboxylic no, n chc k tip nhau trong dy ng ng tc dng vi mt lng d kim loi Ca thu c 5,3 g hn hp 2 mui v gii phng kh H2. CTPT ca 2 axit trn lA. CH3COOH ; C2H5COOH. B. C3H7COOH ; C2H5COOH.C. HCOOH ; CH3COOH. D. C3H7COOH ; C4H9COOH.Hng dnt cng thc chungca hai axit cacboxylic l RCOOH30+ + + + 2 2muimui2RCOOH Ca (RCOO) Ca H5,3 4,16 5,3n 0,03(mol) M 176,7(g/ mol)40 2 0,032(14n 44) 40 176,6 n 1,73CTPT ca 2 axit l 3 2 5CH COOH ; C H COOH.Bi 3.Cho 5,5 g hn hp 2 ancol n chc l ng ng k tip nhau tc dng va vi Na kim loi to ra 8,8 g cht rn v V lt kh H2(ktc). Cng thc ca 2 ancol lA. CH3OH v C2H5OH. B. C2H5OH v C3H7OH.C. C3H7OH v C4H9OH. D. C2H3OH v C3H5OH.Hng dnt cng thc chungca hai ancol n chc l ROH+ +21ROH Na RONa H2 hh8,8 5,5n 0,15(mol)23 1hh5,5M 36,67 14n 18 36,67 n 1,330,15 + CTPT ca hai ancol l CH3OH v C2H5OHBi 4. Khi thy phn hon ton 5,9 g este hai chc to t axit n chc v ancol hai chc th tiu tn ht 5,6 g KOH v thu c 8,4 g mui. Cng thc ca este lA. (HCOO)2C2H4B. (CH3COO)2C2H4C. (CH3COO)2CH2CH2CH3D. CH2(COOC2H5)2Hng dnKOHn 0,1(mol) t cng thc chung ca hai este l 2(RCOO) R'312 2(RCOO) R' 2KOH 2RCOOK R'(OH) + +C 1 mol este mui th (tng)M = 78 R g/molx mol

(tng)m = 8,4 5,9 = 2,5 gR' 2 4R'2,5 1x 0,1 M 28 R':C H78 M 2 este R R5,9M 118(g/ mol) 2(M 44) 28 118 M 10,05 + + Vy cng thc ca este l (HCOO)2C2H4.Bi 5. Thy phn 0,01mol este ca 1 ancol a chc vi 1 axit n chc tiu tn ht 1,2g NaOH. Mt khc khi thy phn 4,36g este th tiu tn ht 2,4g NaOH v thu c 4,92g mui. Cng thc ca este lA. (CH3COO)3C3H5 B. (C2H3COO)3C3H5

C. C3H5(COOCH3)3 D. C3H5(COOC2H3)3Hng dnNaOH1,2n 0,03(mol)40 V nNaOH = 3neste este 3 chc (c to t ancol 3 chc + axit n chc)t cng thc este (RCOO)3R'.(RCOO)3R' +3NaOH (RCOONa)3 + R'(OH)31 mol3 mol 1 mol Khi lng tng : 23.3 R' = 69 R' (g) 0,02 mol0,06 mol 0,06 molKhi lng tng : 4,92 4,36 = 0,56 (g)este0,56n 0,020,9 R' 0,56 = 0,02 (69R') R = 41 R' l C3H5.32Meste = 4,362180,02(g/mol)mR = 218 41 44.3153 R: CH3 Vy cng thc ca este l (CH3COO)3C3H5Bi 6. Thc hin phn ng este ho gia axit axetic (d) v hn hp gm 7,52 g 3 ancol k tip nhau trong cng mt dy ng ng. Sau phn ng thu c 15,92 g 3 este. Gi s hiu sut phn ng l 100%.a) CTPT ca ba ancol l A. 3 2 5 3 5CH OH;C H OH;C H OHB. 2 5 3 5 4 7C H OH;C H OH;C H OHC. 3 5 4 7 5 9C H OH;C H OH;C H OHD. 3 7 4 9 5 11C H OH;C H OH;C H OHb) Ly sn phm ca phn ng este ho trn thc hin phn ng x phng ho va vi NaOH th thu c s g mui thu c l A. 14,5 g B. 16,4 gC. 16,5 g D. 17,8 gBi 7.Cho 16,15 g hn hp NaX v NaY (X, Y l hai halogen hai chu k k tip) vo dung dch AgNO3 d thu c 33,15 g kt ta. Hn hp hai mui ban u l A. NaF v NaClB. NaCl v NaBrC. NaBr v NaI D. Khng xc nhBi 8.Ha tan hon ton 20,85 g hn hp X gm NaCl v NaI vo nc c dung dch A. Sc kh Cl2 d vo dung dch A. Kt thc th nghim, c cn dung dch thu c 11,7 g mui khan. Khi lng NaCl c trong X lA. 5,85 gB. 7,55 gC. 2,95 g D. 5,10 gBi 9.Cho kh CO qua ng s cha 15,2g hn hp cht rn CuO v FeO nung nng. Sau mt thi gian thu c hn hp kh B v 13,6g cht rn C. Cho hn hp kh B hp th hon ton vo dung dch Ca(OH)2 d thy c kt ta. Lc ly kt ta v sy kh ri cn th khi lng kt ta thu c l33A. 12g B. 11gC. 10g D. 9 gBi 10. Nhng thanh kim loi M (ha tr II) vo dung dch CuSO4, sau mt thi gian ly thanh kim loi ra thy khi lng gim 0,1%. Mt khc cng nhng thanhkimloi trnvodungdchAgNO3. Saumt thi gianthykhi lng tng 7,55%. Bit s mol CuSO4 v AgNO3 tham gia phn ng hai trng hp nh nhau. Kim loi M lA. ZnB. Mg C. NiD. CaBi11.Ha tan 3,23g hn hp mui CuCl2v Cu(NO3)2vo nc thu c dung dch X. Nhng thanh Mg vo dung dch X cho n khi mt mu xanh ca dung dch, ly thanh Mg ra cn li, thy tng thm 0,8 g. C cn dung dch sau phn ng thu c m g mui khan. Gi tr m lA. 3,08B. 4,03 C. 2,48D. 2,84Bi 12. Cho 16,2 g hn hp este ca ancol metylic v hai axit cacboxlic no, n chc tc dng va vi dung dch NaOH 1M thu c dung dch A. C cn dung dch A thu c 17,8 g hn hp hai mui khan, th tch dung dch NaOH 1 M dng lA. 0,2 lt B. 0,3 ltC. 0,4 lt D. 0,5 ltBi 13.un nng 3,188 g este ca glixerol vi ba axit cacboxylic no, n chc mch h X, Y, Z (X, Y l ng phn ca nhau v k tip vi Z) vi dung dch NaOH d, phn ng kt thc thu c 3,468 g hn hp mui. Cng thc phn t ca cc axit lA. C2H4O2 v C3H6O2B. C3H6O2 v C4H8O2C. C4H8O2 v C5H10O2D. C3H4O2 v C4H8O2343.Phng php s dng nh lut bo ton in tchC s Trong phn ng oxi ha kh th tng s mol e m cc cht kh cho i bng tng s mol e m cc cht oxi ho thu vo : echo enhnn nNu bi ton c nhiu cht oxi ho v nhiu cht kh tham gia trong s phn ng, hoc qu trnh phn ng phi i qua nhiu giai on th p dng phng php ny gii s rt nhanh v kt qu thu c chnh xc.Cc bcp dng phng php bo ton electron nh sau : Phi xc nh c t cc cht ban u tham gia phn ng n cc cht sn phm c bao nhiu cht cho electron v s mol tng cht, c bao nhiu cht nhn electron v s mol tng cht (c th phi t n s). Vit cc qu trnh cho electron tnh tng s mol e m cc cht kh cho i (e chon ). Vit cc qu trnh nhn electron tnh tng s mol e m cc oxi ho nhn vo ( enhnn). p dng nh lut bo ton electron : echo enhnn ni vi nhng h trung ho in Nu trong h tn ti ng thi cc ht mang in th ta lun c tng s mol in tch dng nt(+)bng tng s mol in tch m nt() : nt(+) =nt() Vi nt = s mol ion s n v in tch ca ion .35Bi tp minh hoBi 1. Ho tan ht 7,5 g hn hp Al v Mg trong HNO3 long thu c dung dch A gm 2 mui v 3,36 lt ( ktc) hn hp 2 kh NO v N2O, khi lng ca hn hp kh l 5,2 g. Khi lng ca Al, Mg trong hn hp ln lt lA. 3,5g v 4,0g. B. 2,1g v 5,4g.C. 2,7gv 4,8g. D. 4g v 3,5g. Li giit 2NO N On a(mol); n b(mol) 3,36a b 0,15 a 0,1mol22,4b 0,2mol30a 44b 5,2+ ' '+ S phn ng :AlMg +HNO3 3 33 2Al(NO )Mg(NO )+2NON O+H2OCc cht cho electron : Al : x (mol) ; Mg : y (mol)Al0 Al3++3ex3x + echon 3x 2y(mol) Mg0 Mg2+ +2ey 2y Cht nhn electron l HNO3 c hai qu trnh nhn e :N+5+ 3e N+2 (NO) 0,30,1 0,1 enhnn 0,7 (mol)

N+5+ 4e N+(N2O) 0,40,1 0,05p dng s bo ton electron ta c :3x + 2y = 0,7(1)36Phng trnh khi lng : 27x + 24y = 7,5(2) Gii h (1, 2) AlMgm 2,7gx 0,1(mol)m 4,8gy 0,2(mol) ' ' Bi 2.Ha tan hon ton hn hp gm 0,06 mol FeS2v x mol Cu2S vo axit HNO3 (va ) thu c dung dch A (ch cha hai mui sunfat) v kh duy nht NO. Gi tr ca x lA. 0,04B. 0,06 C. 0,12D. 0,03Li gii 3 22 42 22 4FeS Fe 2SO0,06 0,06 0,12Cu S 2Cu SOa 2a a+ + + +Theo nh lut bo ton in tch nt(+) =nt() 3.0,06 2.2a 2.0,12 2.a a 0,03(mol) + + Bi 3. Ho tan 3,81 g hn hp Zn v Fe vo dung dch HNO3 thu c dung dch A v 1,12 lt hn hp kh D ( ktc) gm NO v NO2 (gi thuyt NO2 tn ti ktc). T khi ca hn hp D so vi hiro l 16,75. Khi lng kim loi Fe v Zn phn ng ln lt lA. 0,6g v 3,21g. B. 0,56g v 3,25g.C. 1,15g v 2,76g. D. 1,68g v 2,13g.Li gii 2NO NOn a(mol); n b(mol) + ' '+ 1,12a b 0,05 a 0,04(mol)22,4b 0,01(mol)30a 46b 1,67537FeZn + HNO3 3 33 2Fe(NO )Zn(NO )+ 2NONO+H2OCc cht cho electronAl : x (mol) ; Zn : y (mol)Fe

Fe3++3ex 3x + echon 3x 2y Zn Zn2+ +2ey 2yCht nhn electron : HNO3 N+5+ 3e N+2 (NO)0,120,04 0,04 + enhnn 0,12 0,01 0,13 N+5+ e N+4 (NO2)0,010,01 0,01p dng s bo ton electron ta c :3x + 2y = 0,13(1)Phng trnh khi lng :56x + 65y = 6,5 2,69 = 3,81(2) Gii h (1, 2) 'AlMgm 0,56gm 3,25g Bi 4. Hn hp X gm Fe v kim loi M ha tr khng i. Ha tan ht 2,51 g X trong dung dch HCl thy c 0,896 lt H2(ktc) bay ra. Nu ha tan cng lng hn hp X trn vo dung dch HNO3 thu c 0,672 lt NO duy nht (ktc). Kim loi M lA. ZnB. Al C. CuD. Cr Li giiGi Fe Mn x(mol) ;n y(mol) Ta c : 56x + My = 2,51 (I)Cc cht cho e l Fe ; M 382nFe Fe 2ex 2xM M ney ny++ + +e(cho)n 2x ny +Cht nhn e : 22H 2e H0,08 0,04++ e(nhn)n 0,08 Ta c 2x + ny = 0,08 (II)Tng t ta c phng trnh : 3x + ny = 0,09 (III)Gii v bin lun h (I), (II) v (III) ta c MM = 65 Ml ZnBi 5. Ho tan hon ton 24,3 g Al vo dung dch HNO3 long d thu c hn hp kh NO v N2O c t khi hi so vi H2l 20,25 v dung dch B ch cha mt mui.Th tch kh thot ra ktc lA. 8,96 lt B. 4,48 ltC. 11,2 lt D. 2,24 ltLi giiS phn ng23 3 3 2N OAl + HNO Al(NO )++ H O NO

Cht cho electron l Al c s mol24,30,9(mol)273+AlAl + 3e0,92,7 echon 2,7mol.Cht nhn electron l HNO339 +5 +2+5 +2 N +3e N NO3xxx2N +8e2N N O8y2y y Ta c + '+ +3x 8y 2,730x 44y 40,5.(x y)x 0,1V 0,4.22,4 8,96y 0,3 '(lt)Bi 6. Khi cho m g Fe tc dng va vi V lt dung dch HNO3 thu c dung dch mui, 0,1 mol kh NO v 0,3 mol kh NO2. m c gi tr lA. 12,5g B. 11,5gC. 11,2g D. 15,2gLi giiCht cho e Cht nhn e3 5 25 42Fe Fe 3e N 3e N NOm m3 0,3 0,1 0,156 56N e N NO0,3 0,3 0,3+ + ++ + + + + p dng nh lut bo ton e 3m56= 0,6 m 11,2g. Bi 7.Ho tan8,45gZn vo3 ltdung dchHNO3,thu cdungdchAv 2,688 lt hn hp NO v N2O4 (ktc). Khi lng ca 1 lt hn hp kh ktc lA. 2,689g B. 7,252gC. 7,068g D. 3,646gLi gii+ + +3 3 2 22 4NOZn HNO Zn(NO ) H ON O40t 2 4NO N On xmol ; n ymol .Cht cho electron : Zn (0,13 mol) Cht nhn electron : HNO3

2 5 25 42 4Zn Zn 2e N 3e N (NO)0,13 0,26 3x x xN e N (N O )2y 2y y+ + ++ + + + + e(cho) enhnn 0,26 3x 2y n (1) + Tng s mol kh x y 0,12 + (2)t (1) v (2) x =0,02 mol;y =0,2 mol. mhn hp = 0,02.30 + 0,2.92 = 19 (g) ng vi 2,688 ltVy 1 lt hn hp c khi lng l 19.12,6887,068g.Bi 8. Cho 15,5g hn hp 2 kim loi Al, Cu tc dng vi HNO3 va thu c 6,72 lt hn hp hai kh NO, NO2 (2NO NOn : n 2: 1) v hn hp hai mui. Thnh phn % khi lng Cu v Al trong hn hp ln lt lA. 82,25% ; 17,75%. B. 82,58% ; 17,42%.C. 63,84% ; 36,16%. D. 36,16% ; 63,84%.Li giiGi Al Cun x(mol) ; n y(mol) . Ta c 27x + 64y = 15,5 (I)Theo gi thit ta tm c2NO NOn 0,2(mol) ; n 0,1(mol) Cht cho eCht nhn e3 5 22 5 42Al Al 3e N 3e N (NO)x 3x 0,6 0,2Cu Cu 2e N e N (NO )y 2y 0,1 0,1+ + ++ + + + + + + 41p dng nh lut bo ton e : 3x + 2y = 0,7 (II)Gii h (I) v (II) thu c x = 0,1 (mol) ; y = 0,2 (mol)%mAl = 17,42% ; %mCu = 82,58%Bi 9. Ho tan 11,2 g Fe bng dung dch H2SO4 (long, d) thu c dung dch X v 5,6 lt kh bay ra ktc. Dung dch X phn ng va vi V ml dung dch KMnO4 0,5M. V c gi tr lA. 500ml B. 100mlC. 150ml D. 200mlLi giiCht cho eCht nhn e 327 2Fe Fe 3e 2H 2e H0,2 0,6 0,5 0,25Mn 5e Mn0,1 0,6 0,5+ ++ + + + + 4KMnO0,1V 0,2(lit)0,5 Bi 10. m g Fe ngoi khng kh mt thi gian nn b g (gi s g st ch ton l oxit st) cn nng 10 g. Lng g st trn lm mt mu hon ton 200 ml dung dch KMnO4 0,5M trong dung dch H2SO4 d. m c gi tr lA. 17,2gB. 9,8gC. 9,0g D. 15,0gLi giiS phn ng :2 a 4 2 4 2 4 3 4 2Fe+O FeO KMnO H SO Fe (SO ) MnSO H O + + + + Cht cho electron : Fe : m(mol)56 Fe Fe3++ 3e 42

m56 3m56 echomn 3.56 Cht nhn electron O :10 m16(mol) v KMnO4 : 0,1 (mol) O+2e O2

10 m16210 m16

Mn+7 +5e Mn+2 0,10,5 e nhn10 mn 2. 0,516 +p dng s bo ton electron :10 m m2. 0,5 3. m 9,8(g)16 56+ Bi 11.Thi lung khng kh i qua m(g) bt st nung nng sau mt thi gian bin thnh hn hp A c khi lng 30g gm Fe, FeO, Fe2O3, Fe3O4. Cho A phn ng hon ton vi dung dch HNO3 thy gii phng ra 5,6 lt kh NO duy nht (ktc). Khi lng ca m lA. 27,5gB. 22,5gC. 26,2g D. 25,2gLi giiS : + + +'2 2 3 3 3 3 23 4Fe, FeOFe +O Fe O HNO Fe(NO ) NO H OFe O Cht cho electron Fe, s mol : m.56 Fe Fe3++ 3e 43

m56 3m56 echomn 3.56 Cht nhn electron O2, s mol : 30 m32 v HNO3. O+2e O2

30 m16230 m16

N+5 +3e N+2 (NO) 0,750,25 0,25 + e nhn30 mn 2. 0,7516p dng s bo ton electron :+ 30 m m2. 0,75 3. m 25,2(g)16 56Bi 12. Nung nng 5,6 g bt st trong bnh ng O2 thu c 7,36 g hn hp X gm Fe, Fe2O3v Fe3O4. Cho X tan hon ton trong dung dch HNO3thu c V lt (ktc) hn hp kh Y gm NO v N2O4, t khi hi ca Y so vi H2 l 25,33. V c gi tr lA. 22,4 lt B. 0,672 ltC. 0,372 lt D. 1,12 ltLi giiGi 2 4NO N On x(mol); n y(mol) 2Y /H30x 92yd 25,33(x y).2+ +(1) + + +' '2 2 3 3 3 3 22 43 4FeNOFe +O Fe O HNO Fe(NO ) H ON OFe O

44Cht cho electronFe :0,1 mol+ +3Fe Fe 3e0,1 0,3 echon 0,3mol eCht nhn electronO :7,36 5,60,11(mol)16v HNO3. 25 25 42 4O 2e O0,11 0,22N 3e N (NO)3x x xN e N (N O )2y 2y y+ ++ ++ + + + + enhnn 3x 2y 0,22(mol e)0,3 3x 2y 0,22 + +(2)T (1), (2) x = 0,02 mol ; y = 0,01 mol.Vy V = (0,02 +0,01)22,4 = 0,672 lt.Bi 13. Cho 6,64 g hn hp A gm Fe, FeO, Fe2O3, Fe3O4 vo dung dch HNO3 long, d thu c V lt hn hp kh B ( 30oC, 1 atm) gm NO, NO2 (vi 2NO NOn : n 2). Mt khc khi cho lung kh H2 d i qua hn hp A nung nng, sau khi phn ng hon ton thu c 5,04 g Fe. Th tch hn hp kh B lA. 0,464 lt B. 0,672 ltC. 0,242 lt D. 0,738 ltLi giiFeFeO +H2 Fe + H2OFe2O3Fe3O4O(A) Om 6,64 5,04 1,6(gam) n 0,1(mol) 45FeFeONOFe+O2 Fe2O3+HNO3Fe(NO3)3 + +H2OFe3O4 NO2Cht cho electron l Fe : 5,040,09(mol)56Fe Fe3++ 3e0,090,27Cht nhn electron l :O+ 2eO20,10,2N+5 +3eN+2 (NO)6x 2xN+5 + eN+4 (NO2)xx 0,2 + 6x + x = 0,27 x 0,01 tng s mol 2 kh = 3x = 0,03 mol.Gii h tm c 0,03.0,082.300V 0,7381 lt.Bi 14.Cho lung kh H2i qua ng s ng m g oxit Fe2O3 nhit cao mt thi gian, ngi ta thu c 6,72 g hn hp A gm 4 cht rn khc nhau. em ho tan hon ton hn hp ny vo dung dch HNO3 d thy to thnh 0,448 lt kh B ktc (duy nht) c t khi so vi hiro l 15 th m c gi tr lA. 7,5 g B. 7,2 gC. 8,0 g D. 8,4 gLi giiS :46 2 3 2 2Fe O H H O A + +3HNO + Fe(NO3)3 + NO + H2OXt c qu trnh th : Fe+3Fe+3 hnh nh khng c s cho v nhn e.Cht cho electron : H2 m 6,72(mol)16( do2 (oxit) 2H O H O + )m 6,72 m 6,7216 16 H2 2H+ +2e m 6,72162m 6,7216= echon Cht nhn electron : HNO3, kh B l NO.N+5 + 3eN+2 (NO ) 0,06 0,020,02 enhnn 0,06 m 6,720,06 m 7,2g8 Bi15.Trn 60g bt Fe vi 30gbt lu hunh ri un nng (trong iu kin khng c khng kh) thu c cht rn X. Ho tan X bng dung dch axit H2SO4 long, d c dung dch B v kh C. t chy C cn V lt O2 (ktc). Cc phn ng xy ra hon ton th V c gi tr lA. 39,2 lt B. 32,928 ltC. 32,29 lt D. 38,292 ltLi giiS : ' ' ' ' o2 4 2H SO + O t 2 242 2H H O Fe FeFeSO+S FeS H S SOXt c qu trnh phn ng th Fe v S cho electron, cn O2 nhn electron.Cht cho electron : Fe : 60(mol)56 ;S : 30(mol)3247 Fe Fe2+ +2e

605626056 SS+4 (SO2)+4e

303243032 Cht nhn electron : gi s mol O2 l x mol.O2+4e 2O2 x4xp dng s bo ton electron : 4 .32302 .56604 + x Gii ra x = 330224 mol 2O330V 22,4 33224 (lt)Bi 16. Hn hp X gm FeS2v MS c s mol nh nhau (M l kim loi ha tr II). Cho6,51gX tcdng hon ton vi lng d dung dch HNO3un nng, thu c dung dch Y (ch cha mui sunfat) v 13,216 lt (ktc) hn hp kh Z gm NO v NO2 c khi lng 26,34g. Kim loi M lA. MgB. Zn C. MnD. CuLi giiS phn ng :2FeSMS + HNO3 Y+2NONO + H2OT gi thit ta tnh c 2NO NOn 0,05(mol) ; n 0,54(mol)Cht cho e : 2FeS , MS 48+ ++ + + + + +3 622 6FeS Fe 2S 15ex 15xMS M 2S 8ex 8x e(cho)n 23x(mol e)Cht nhn e : HNO3+ ++ ++ + 5 25 42N 3e N (NO)0,15 0,05N e N (NO )0,54 0,54 e(nhn)n 0,69(mol e)23x = 0,69 x = 0,03 (mol)120x +(M+32)x=6,51 M=65: CuBi 17.Ho tan hon ton 12,8g kim loi Cu vo dung dch HNO3 long, tt c kh NO thu c em oxi ho thnh NO2 ri sc vo nc c dng oxi chuyn ht thnh HNO3. Th tch kh oxi ktc tham gia vo qu trnh trn lA. 2,28 ltB. 4,48 ltC. 2,24 lt D. 6,72 ltLi giiS :HNO3 + Cu Cu(NO3)2 + H2O + NO 2O + NO22O + HNO3Xt c qu trnh th coi nh Cu cho e v O2 nhn e :Cht cho electron : Cu ; 0,2 mol.Cu Cu2++2e0,2 0,4Cht nhn electron : O2O2+ 4e 2O249x 4x4x = 0,4 x = 0,1 2OV= 0,1 . 22,4 = 2,24 (lt)Bi 18.Chia 5,56 g hn hp gm Fe v kim loi A (c ho tr n) lm hai phn bng nhau : Phn 1 ho tan ht trong dung dch HCl c 1,568 lt hiro. Phn 2 ho tan ht trong dung dch HNO3 long thu c 1,344 lt kh NO duy nht v khng to ra NH4NO3. Cc kh c o ktc. Tn kim loi A lA. Mg B. AlC. Zn D. CrLi giiTrong mi phn th Fe : x(mol) ; A : y(mol) l cc cht cho electron : H+ v N+5 l cc cht nhn electron.p dng nh lut bo ton e cho tng phn ta c h:56x My 2,78 x 0,042x ny 0,14 ny 0,063x ny 0,18 A 9n+ + ' ' + gi tr ph hp n = 3, A = 27 :AlBi 19.Cho 1,15 g hn hp gm Cu, Mg, Al tc dng ht vi dung dch HNO3 thu c hn hp kh gm 0,1 mol NO vo 0,4 mol NO2. Khi lng mui nitrat to ra trong dung dch lA. 45,69g B. 64,59gC. 44,55gD. 34,69gLi giit x, y, z ln lt l s mol Cu, Mg, Al.CuCu(NO3)2NOMg+HNO3 Mg(NO3)2 + +H2O 50AlAl(NO3)3NO2mmui =m3KL + 3NOmTa c: 2x + 2y + 3z = 0,3 + 0,4 = 0,7(1)Nhng 0,07 cng chnh l s mol 3NO to mui vi ion kim loi.Khi lng mui nitrat l : 1,15 + 62.0,7 = 44,55g.Bi 20.Cho m g hn hp ba kim loi Al, Fe, Cu tan hon ton trong dung dch HNO3 thu c V lt hn hp kh D (ktc) gm NO2 (gi thit tn ti NO2 ktc) v NO (khng sinh mui NH4NO3). T khi hi ca D so vi hiro bng 18,2. Tng s g mui khan to thnh theo m v V lA. m + V22,4B. m V22,4C. 2m + V22,4 D. 2m V22,4Li giiNOM+ HNO3 M(NO3)n++ H2ONO2

T gi thit ta tnh c 2NO NO4V 2Vn (mol);n (mol)112 112 Cht nhn electron :HNO3N+5+3e N+2 (NO) 12V112

4V112 N+5+ e N+4 (NO2) enhn14Vn112

2V112 2V11251Cht cho electron : M cho i 14V112 mol e = s mol in tch (+) = s mol in tch () ca NO3 to mui = 3NOn :mmui = mKL + 3NOm = m + 62.14V112 = m + V(gam)7,75Bi 21.Ha tan hon ton hn hp hai kim loi gm 0,02 mol A (ha tr II) v 0,03 mol B (ha tr III) cn V ml dung dch HNO32M. Sau phn ng thu c V1 lt hn hp hai kh NO v N2O c t khi so vi H2 l 15,35. V c gi tr lA. 0,076 B. 0,086 C. 0,069 D. 0,179Li giiS phn ngAB+ 3HNO 3 23 3A(NO )B(NO ) +2NONO+2H O p dng phng php bo ton electron o 2 5 2o 3 52Qu trnh cho e Qu trnh nhn eA A 2e N 3e N (NO)0,02 0,04 3x x xB B 3e N 4e N (N O)0,03 0,09 8y 2y y+ + ++ + + + + + + Ta c h 2NON O3x 8y 0,13x n 0,038mol30x 44yy n 0,002mol 15,352(x y)+ +' ' +p dng nh lut bo ton nguyn t N :3 3 2 3 3 2HNO A(NO ) B(NO ) NO N On 2n 3n n n 0,172(mol) + + + V = 0,086 (lt)52Bi tp vn dngBi 1. Dung dch X c cha 5 ion : Cu2+, Ba2+ , Ca2+v 0,1mol Clv 0,2mol 3NO. Thm dn V lt dung dch K2CO3 1M vo dung dch X n khi c kt ta cc i. V c gi tr lA. 150ml B. 300mlC. 200ml D. 250mlHng dnDung dch lun trung ho v in 3 3CO Cl NO2n n n + + 323Cl NOCOn nn 0,15(mol)2 2 3ddK CO0,15V 0,151(lt) = 150 mlBi 2.Mt dung dch X cha 0,2 mol K+, 0,2 mol Cu2+, a molError! Objects cannotbecreated fromediting field codes.. Thm lng d dungdch hn hp Y gm BaCl2 v NH3 vo dung dch X thu c m g kt ta. Gi tr ca m lA. 69,9 g B. 88,5 gC. 77,8 g D. 87,5 gHng dnDung dch X lun trung ha v in nn : 2a = 0,2 + 2.0,2 a = 0,3 (mol)Cho Y vo X kt ta thu c :+ + 2 24 4Ba SO BaSO0,3 0,3m 0,3.233 69,9(gam)Bi3.Cho0,04 molFe; 0,02molAltcdng vi100 ml dungdchXcha AgNO3 v Cu(NO3)2 thu c dung dch Y v 5,84 g cht rn D gm 3 kim loi. ChoDtcdngvidungdchHCldc0,448lthiro(ktc). Nng mol cc mui AgNO3 v Cu(NO3)2 trong X ln lt l53A. 0,4M; 0,2M B. 0,2M; 0,4MC. 0,4M; 0,6M D. 0,2M; 0,3MHng dnS :Al Ag+ Ag + Cu2+Fe(d)+ Cu Fe H+H2 Cht cho electron : Al (0,02 mol) v Fe (0,06 mol).AlAl3++3e0,02 0,06 echon 0,14molFe Fe2+ + 2e 0,040,08Cht nhn electron : Ag+ (x mol) ; Cu2+ (y mol) ; H+ (0,04 mol)Ag++ e Agx xxCu2++2e Cu + + enhnn x 2y 0,04y2y y 2H++ 2e H2 0,04 0,02(Fed + 2H+ Fe2++H2) + + ' ' ' + + 33 2M AgNO )D M Cu(NO )C 0,2Mx 2y 0,04 0,14 x 0,02m x.108 y.64 0,02.56 5,84 y 0,04 C 0,4MBi 4. Ho tan hon ton mg hn hp 3 kim loi Al, Fe, Mg trong dung dch HCl thy thot ra 13,44 lt kh. Cng lng hn hp trn tc dng vi dung dch 54CuSO4 d, lc ly ton b cht rn thu c sau phn ng tc dng vi dung dch HNO3 nng d th thu c V lt kh NO ( ktc).Th tch kh NO thu c lA. 17,92 lt B. 13,76 lt C. 13,44 ltD. 44,8 lt Hng dnTa c m g (Al, Mg, Fe) cho electron ; Cu2+ nhn c s mol electron = s mol e m H+ nhn c = s mol e m N+5 nhn c. 2H+ H2+ 2e0,61,2 mol e Cu2+ Cu + 2e 1,2 mol eN+5 +3e N+2(NO)1,20,4 0,42 4N OV 0,4.22,4 8,96(lt) Bi 5. Ho tan m g hn hp A gm Fe v kim loi R (c ho tr khng i) trong dung dch HCl d th thu c 1,008 lt kh (ktc) v dung dch cha 4,575g mui khan. Cng lng hn hp trn ha tan trong dung dch cha hn hp HNO3 c v H2SO4 nhit thch hp th thu c 0,063 mol kh NO2 v 0,021 mol kh SO2. Kim loi R lA. Mg B. AlC. Ca D. ZnHng dnTrong phn ng vi HCl, Fe x(mol) ; R y (mol) cho e. H+ nhn e.Fe Fe2++ 2ex2xR Rn+ + ne55y ny2H++ 2e H20,09 0,09 0,045Ta c : 2x + ny = 0,09(1) Phng trnh khi lng 2 mui : 56x + My + 0,09.35,5 = 4,575(2) Trong phn ng vi HNO3, H2SO4 c cc qu trnh : Fe Fe3++ 3e x 3xRRn+ +neynyN+5 + e N+4(NO2)0,0630,063 0,063S+6 + 2e S+4 (SO2)0,0420,0210,021Ta c : 3x + ny = 0,105 (3)R RR2x +ny =0,09x 0,01556x +M y +0,09.35,5 =4,575ny 0,06 M 27 RlAlM 9n 3x +ny =0,105 ' ' Bi 6. Cho 23,6g hn hp Cu, Ag tc dng ht vi V lt dung dch HNO3 1M thu c hn hp mui v 0,5 mol kh NO2 bay ra. Thnh phn % khi lng mi kim loi trong hn hp lA. 52,25% ; 47,75% B. 54,23% ; 45,77%C. 54,00% ; 46,00% C. 52,34% ; 47,66% Hng dn563 23 2 23Cu Cu(NO )HNO NO H OAg AgNO+ + +Cht cho e Cu : x ; Ag : y(mol) Cht nhn e : HNO32 5 423 2 2Cu Cu 2e N e N NOx 2x 0,5 0,5(mol)Ag Ag e (hoc NO e 2H NO H O)y y+ + ++ + + + + + + +e(cho) e(nhn)n 2x y 0,5 n + Ta c h CuAg%m 54,23%64x 108y 23,6 x 0,2%m 45,77%2x y 0,5 y 0,1 + ' ' '+ Bi 7. 10,08 g bt st trong khng kh sau mt thi gian thu c hn hp A c khi lng m g gm Fe, FeO, Fe3O4, Fe2O3. Cho A tc dng hon ton vi dung dch HNO3thy gii phng ra 2,24 lt kh NO duy nht ( iu kin tiu chun). Khi lng m ca hn hp A lA. 11 g B. 12gC. 13g D. 14gHng dnS phn ng2 2 3 3 3 3 23 4Fe, FeOFe +OFe O HNO Fe(NO ) NO H OFeO + + +- Cht cho e :Fe 0,18 molFe Fe3++ 3e 0,180,54 e(cho)n 0,54(mol) Cht nhn e : O2 :m 10,08(mol)32; HNO357O + 2e O2- m 0,18 m 0,1816 8 N+5 +3e N+2 NO0,3 0,10,1e(nhn)m 10,08n 0,38 + p dng LBT e : m 10,080,3 0,54 m 12(gam)8+ 4.Phng php ng cho trong bi ton trn ln hai dung dch hoc hn hp hai khC sp dng nh lut bo ton khi lng trong qu trnh trn ln cc dung dch ca cng mt cht tan, ta lun c : Khi lng dung dch thu c bng tng khi lng ca cc dung dch thnh phn. Khi lng cht tan thu c cng bng tng khi lng cht tan c trong tng dung dch thnh phn . 58Phm vi p dng Pha long hay c cn dung dch Pha trn cc dung dch ca cng mt cht, cng loi nng Pha trn cc khKhi trnln2dungdchcnngkhcnhauhaychothmcht tan nguyn cht vo dung dch cha cht tan , hoc qu trnh c cn dung dch. tnh c nng dung dch trng thi cui ta c th gii bng phngphpbotonkhi lng, tuynhintanndngphngphp ng cho th gii bi ton s nhanh hn.Sau y gii thiu mt s s hay c s dng :Nu trn dung dch 1 c khi lng l m1(g) v nng C1% vi dung dch 2 c khi lng m2(g) v nng C2% (gi s C1< C2) thu c dung dch mi c nng C% (vi C1 < C < C2) ta s dng s :

Ch :Ta coi H2O c C% = 0.Ta coi cht tan nguyn cht c C = 100%.Nu trn dung dch 1 c th tch V1 (lt) v nng CM(1) vi dung dch 2 c th tch V2 (lt) v nng CM(2)(gi s CM(1) < CM(2)) ta thu c dung dch mi c nng CM (vi CM(1) < C < CM(2)) ta s dng s sau :

59 m(g)......... C C Cm C CCm C Cm (g).........C C C1 1 21 22 12 2 1 M( ) M( ) MM( ) MMM M( )M( ) M M( )V (lit)...... C C CC CVCV C CV (lit)...... C C C1 1 2212 12 2 1Nu trn mt th tch V1 (lt) kh A c phn t khi MA vi mt th tch kh B c phn t khi MB (gi s MA < MB) ta thu c hn hp kh c phn t khi trung bnh l M (viMA < M< MB) ta s dng s sau :

Bi ton minh hoBi 1.Cn trn V1ml dung dch HCl 2M vi V2ml dung dch HCl 0,5M thu c 300 ml dung dch HCl 1M. Gi tr V1, V2 ln lt lA. V1 = V2 = 150 B. V1 = 100, V2 = 200C. V1 = 200, V2 = 100 D. V1 = 50, V2 = 250Li giiTa c 12 1 21 2V 1V 2 V 100ml ; V 200mlV V 300 '+ Bi 2.Cn cho s g H2O vo 100 g dung dch H2SO490% c dung dch H2SO4 50% lA. 90 g B. 80 gC. 60 g D. 70 gLi gii60m 0 40 50

100 90 50A BBAB AV (lit)...... M M Mn V M MMn V M MV (lit)...... M M M 11 12 22V12 0,5 1 V2 0,5 1 m 40m 80(gam)100 50Bi 3. Lm bay hi 500 ml dung dch cht A 20% (D = 1,2 g/ml) ch cn 300 g dung dch. Nng % ca dung dch ny lA. 30% B. 40%C. 50% D. 60%Li giimdd = 500.1,2 = 600 (g)y l bi ton c cn nn s : 600 xx 40%300 x 20 Bi 4.Trn V1ml dung dch NaOH (d = 1,26 g/ml) vi V2ml dung dch NaOH (d = 1,06 g/ml) thu c 1lt dung dch NaOH (d = 1,16 g/ml). Gi tr V1, V2 ln lt lA. V1 = V2 = 500 B. V1 = 400, V2 = 600C. V1 = 600, V2 = 400 D. V1 = 700, V2 = 300Li gii 11 22V 0,1V V 500mlV 0,161dungdchA:600 20 - x xH2O: 300 x - 20 V1 1,260,1 1,16V2 1,06 0,1Bi 5.T 200g dung dch KOH 30% c dung dch 50% cn thm vo s g KOH nguyn cht lA. 70 g B. 80 gC. 60 g D. 90 gLi gii m 20m 80g200 50Bi 6. Mt dung dch HNO3 nng 60% v mt dung dch HNO3 khc c nng 20%. c 200g dung dch mi c nng 45% th cn phi pha ch v khi lng gia 2 dung dch HNO3 60%, 20% ln lt lA. 75g ; 125g. B. 125g ; 75g.C. 80g ; 120g. D. 100g ; 100g.Li gii + 121 2m 15 3m 25 5m m 200 '12m 75gm 125gBi 7. Mt hn hp 104 lt (ktc) gm H2 v CO c t khi hi i vi metan bng 1,5 th 2HVv VCO trong hn hp lA. 16 lt v 88 lt. B. 88 lt v 16 lt. C.14 lt v 90 lt. D. 10 lt v 94 lt.62m 1002050

200 3050m120 1545m26025Li gii12V 2V 11 '12V 16ltV 88ltBi 8. Cho 6,12g Mg tc dng vi dung dch HNO3 thu c dung dch X ch c mt mui v hn hp kh Y gm NO v N2O c t khi hi i vi hiro bng 16,75. Th tch NO v N2O ( ktc) thu c ln lt lA. 2,24 lt v 6,72 lt.B. 2,016 lt v 0,672 lt.C. 0,672 lt v 2,016 lt. D. 1,972 lt v 0,448 lt. Li giiQu trnh cho electron :Mg Mg2+ +2e 0,225 0,51Qu trnh nhn electron : N+5+3e N+2 (NO)3xxN+5+4e N+ (N2O) 8y 2yy 2N ONOV1 xV 3 y3x 8y 0,51 x 0,093x y 0 y 0,03+ ' ' 63V1 H2 2 424V2 CO28 22V1 NO3010,5 33,5V2 N2O44 3,5Bi tp vn dng Bi 1. Trn hai th tch metan vi mt th tch hirocacbon X thu c hn hp kh (ktc) c t khi so vi H2 bng 15. Cng thc phn t ca X lA. C2H6B. C3H8C. C4H10D. C5H12Bi 2.Cho hn hp X gm 2 este c CTPT l C4H8O2v C3H6O2tc dng vi NaOH d thu c 6,14g hn hp 2 mui v 3,68g ancol B duy nht c t khi so vi oxi l 1,4375. S g ca C4H8O2 v C3H6O2 trong A ln lt lA. 3,6g v 2,74g. B. 3,74g v 2,6g.C. 6,24g v 3,7g. D. 4,4g v 2,22g.Hng dnMB = 1,4375.32 = 46 ancol B l C2H5OH.nB = nmui = 3,6846= 0,08 (mol) mui6,14M 76,75(g/ mol)0,08p dng quy tc ng cho: ' ' 4 8 23 6 2C H OC H Om 4,4gx 0,05x 5y 3 y 0,03 m 2,22gBi 3.T1tnqunghematit (A)iuchc400kgst. T1tnqung manhetit (B) iu ch c 500kg st. c 1 tn qung hn hp m t 64yHCOONa 68 5,25

76,75

x CH3COONa 82 8,751 tn qung hn hp ny iu ch c 460kg st th phi trn 2 qung A. B vi t l v khi lng lA. 2 : 3 B. 3 : 5C. 3 : 4D. 1 : 3Hng dn ABm 40 2m 60 3Bi 4. Mt hn hp kh X gm SO2 v O2 c t khi so vi metan bng 3. Thm V lt O2 vo 20 lt hn hp X thu c hn hp Y c t khi so vi metan bng 2,5. Gi tr ca V lA. 20B. 30C. 5 D. 10Hng dnTrong 20 lt X ban u th th tch mi kh : 11 22V 16V V 10(lit)V 16Khi thm V lt O2 vo 20 lt hn hp X thu c hn hp Y : +10 1V 20(lit)10 V 365mA400 40 460

mB 50060V1SO2 64 16

48

V2 O232 1610SO2648

40

10 + V O2 32 24Bi 5.S ml H2O cn thm vo 1 lt dung dch HCl 2M thu c dung dch mi c nng 0,8M lA. 1,5 lt B. 2 ltC. 2,5 lt D. 3 ltBi 6. Trn 1 lt dung dch KCl C1 M (dung dch A) vi 2 lt dung dch KCl C2 M (dung dch B) c 3 lt dung dch KCl (dung dch C). Cho dung dch C tc dng va vi dung dch AgNO3 thu c 86,1 g kt ta. Nu C1= 4C2 th C1 c gi tr l A.1 M B. 1,2 MC. 1,4 M D.1,5 MHng dnAg Cl AgCl0,6 0,6(mol)+ + 1 22 11lt C 0,6 C0,62lt C C 0,6Z]Z] 1 221 2 2 2 11C 4C0,6 C 1C 0,6 1,2 2C 6C 1,8 C 0,3M ; C 1,2M2 C 0,6 Bi 7.T khi hi ca hn hp kh C3H8v C4H10i vi hiro l 25,5. Thnh phn % th tch ca hn hp lA. 50% ; 50%.B. 25% ; 75%. C. 45% ; 55%. D. 20% ; 80%.5.Phng php dng phng trnh ion rt gnC sBn cht ca cc phn ng trao i xy ra trong dung dch cht in li l phn ng ca cc ion vi nhau to ra cht kt ta, bay hi hay cht in li yu,...66Cch p dngKhi cho dung dch hn hp (X) phn ng vi dung dch hn hp (Y) thay v vic vit nhiu phng trnh phn ng gia cc phn t ta vit cc phng trnh dng ion rt gn. Sau y l mt s s minh ha : Cho s : 2 43HClH SOHNO' + 2NaOHBa(OH)' hn hp 6 mui+H2O Bn cht l :H+(axit) + OH(baz) H2O v 2 24 4Ba SO BaSO+ + Khi mi trng trung tnh th : H (axit )n+= OH ( )nbaz Cho s '2 34 2 32 3Na CO(NH ) COK CO + '22BaClCaCl

Bn cht l : + + + '+ 2 23 32 23 3Ca CO CaCOBa CO BaCO Cho s :FeMgZn' + 2 4HClH SO (l)'Hn hp mui+H2 Bn cht l FeMgAl' +H+ Hn hp mui+H2Bi tp minh haBi 1. Cho dung dch X cha ng thi 2 axit H2SO4 1M v HCl 2M vo 200ml dung dch Y cha NaOH 1,5 M v KOH 1M. Khi mi trng dung dch trung tnh th th tch dung dch X cn lA. 120 ml B. 125 mlC. 200 ml D. 150 ml67Li giiBn cht cc phn ng trn l 2H OH H O+ + + + + HOHn V.(2.1 2) 4V (mol)n 0,2.(1,5 1) 0,5(mol)Khi mi trng trung tnh : 4V = 0,5 V= 125 mlBi 2. Cho 100ml dung dch A cha ng thi 2 axit HCl 1M v HNO3 2M vo 200ml dung dch B cha NaOH 0,8 M v KOH x M thu c dung dch C. Bit rng trung ho 100ml dung dch C cn 60ml dung dch HCl 1M. x c gi tr lA. 1,2M B. 2,2MC. 3,3M D. 2,5MLi giiC 3 axit phn ng vi 2 baz. Bn cht cc phn ng l 2H OH H O+ + + + + +HOH60.500n 0,1(1 2) .1 0,6(mol)100.1000n 0,2(0,8 x)(mol)Mi trng trung tnh: 0,6 = 0,2(0,8+x) x = 2,2M.Bi 3. Trn 100ml dung dch X gm KHCO3 1M v K2CO3 1M vi 100ml dung dch Y gm NaHCO3 1M v Na2CO3 1M thu c dung dch Z. Nh t t 100ml dung dch T gm H2SO4 2M v HCl 1M vo dung dch Z thu c V lt CO2 (ktc). Gi tr ca V lA. 2,24 lt B. 8,96 ltC. 6,72 lt D. 4,48 ltLi giiBn cht ca cc phn ng gia cc cht trong T v Z l :6823 33 2 2CO 2H HCOHCO H H O CO + ++ + +Khi cho dung dch X vo Y thu c dung dch Z c 3HCO0,2 (mol) v 23CO0,2 (mol).+ + 2 4HCl H SOH (ddT)n n 2n 0,5(mol)Nh t t dung dch T vo dung dch Z, phn ng xy ra theo th t : + + 23 3CO H HCO0,2 0,2 0,2Tng s mol + 3HCOn 0,2 0,2 0,4(mol)+ < 3H (cnli) HCOn 0,5 0,2 0,3(mol) n 0,4(mol)3H (d ) HCOn 0,5 0,2 0,3 n 0,2 0,2 0,4(mol)+ < + 3 2 2HCO H CO H O0,3 0,3 0,3 ++ +Bi 4. Tnh th tch dung dch cha HCl 0,5M v H2SO4 0,75M cn thit ho tan hon ton 23,2g Fe3O4.A. 200 ml B. 300 mlC. 350 ml D. 400 mlLi giiBn cht phn ng gia hai axit v Fe3O4 l :Fe3O4+8H+ Fe2+ + 2Fe3+ + 4H2O. 0,1 0,8Gi th tch dung dch l V : 0,5V + 2V.0,75 = 0,8 V = 400 ml 69Bi 5.Mt dung dch A cha HCl v H2SO4 theo t l mol l 3 : 1. Cho 100 ml dungdchAtrunghovavi 500ml dungdchNaOHc cha 20g NaOH/lt. Tng khi lng mui thu c sau phn ng lA. 31,175g B. 15,875gC. 42,113g D. 23,175gLi giiGi s mol ca H2SO4 l x (mol) th s mol HCl l 3x molTrong 100ml dung dch A c Hn 5x(mol)+Trong 500 ml NaOH20 500n . 0,25(mol) 5x 0,25 x 0,05(mol)40 1000 24mui cation anionNa Cl SOm m mm m m 0,25.23 3.0,05.35,5 0,05.96 15,875g+ + + + + + Bi 6.Cho 100ml dung dch A cha NaCl 1,5M v HCl 3M vo 100ml dung dch B cha AgNO31M v Pb(NO3)21M thu c dung dch C v kt ta D. Khi lng kt ta D lA. 56,72 g B. 49,13 gC. 34,48 g D. 50,10 gLi giiBn cht cc phn ng xy ra gia A v B l Ag+ +Cl AgClPb2++2Cl PbCl2+ ++ + + 2( )Cl( )Ag Pbn 0,1.(1,5 3) 0,45(mol) nn 0,1mol ; n 0,1mol n 0,1 0,1.2 0,3(mol)t+(A) t-(B)n n > ion Cl d : mmui = 108.0,1 + 0,1.207 + 0,3.62 = 50,10 (g).70Bi 7. Dung dch A cha axit HCl a M v HNO3 b M. trung ho 100 ml dung dchAcndng200ml dungdchhnhpBchaNaOH0,05Mv Ba(OH)2 0,15M. Mt khc kt ta hon ton ion Cl c trong 50ml dung dch A cn 100ml dung dch AgNO3 0,1M. Cc gi tr a, b ln lt l A. 0,2M; 0,1M. B. 0,2M; 0,2M.C. 0,2M; 0,3M. D. 0,1M; 0,2M.Li gii Bn cht cc phn ng xy ra gia A v B l : 2H OH H O+ + + + +HOHn 0,1.(a b) moln 0,2.(0,05 0,15) mola b 0,04 + Bn cht phn ng xy ra gia A v AgCl l Ag Cl AgCl+ + a 0,2M0,05a 0,01b 0,1M 'Bi 8. Cho 2 kim loi Fe, Mg tc dng vi 200ml dung dch A gm HCl 0,1M, H2SO40,2M thu c dung dch B v kh C. Cho t t dung dch D gm NaOH 0,3M, KOH 0,1M vo B tc dng va vi cc cht trong B th th tch dung dch D cn dng lA. 0,15 lt. B. 0,25 lt.C. 0,35 lt. D. 0,45 lt.Li gii++ + ++ + + 222 222Fe Fe Fe(OH)H H H OH H OMg Mg Mg(OH)nh lut bo ton in tch : + ( )n trong B =+Hntrong A =OHntrong D.71Dung dch trung tnh khi :+ + + H OHn n 0,2(0,1 0,2.2) V(0,3 0,1) V 0,25(lt)Bi tp vn dngBi 1. tc dng va vi 0,96g hiroxit ca 2 kim loi kim hai chu k lin tip trong bng tun hon, phi dng 20ml dung dch HCl 0,4M v H2SO4 0,3M. Cc kim loi kim lA. Na, K B. Li, NaC. K, Rb D. Na, RbHng dnGi cng thc chung ca hai hiroxit ROHBn cht cc phn ng :2OH H H O++ ROHH OHn 0,02(0,4 0,3.2) 0,02(mol) n n+ + ROH R R0,96M 48 M 17 48 M 310,02 + Hai km loi kim l Na, K.Bi 2.Ha tan hn hp hai kim loi Ba v Na (dng ht rt nh) vo nc thu c dungdch A v 672 ml kh (ktc). Nh t t dung dch FeCl3 vo dung dch A cho n d, lc kt ta, ra sch, sy kh v nung n khi lng khng i thu cm g cht rn. Gi tr m lA. 3,2 g B. 6,4gC. 1,6 g D. 4,8 gBi 3.Cho 4,64g hn hp A gm FeO, Fe2O3, Fe3O4(2 3FeO Fe On : n 1: 1 ) ho tan hon ton trong V lt dung dch H2SO4 0,2M v HCl 0,6M. V c gi tr lA. 1,60 lt B. 1,22 lt72C. 1,90 lt D. 1,56 ltHng dnDo FeO.Fe2O3 = Fe3O4, vy A xem hn hp ch l Fe3O4 3 4A Fe O4,64n n 0,02232(mol)Fe3O4 + 8H+ Fe2+ + 2Fe3+ + 4H2O0,020,16 0,16 = 0,1V V = 0,161,60,1 (lt)Bi 4. Hn hp cht rn X gm Fe, Fe2O3, Fe3O4 v FeO (c s mol bng nhau l 0,1 mol). Ha tan ht X vo dung dch Y gm HCl v H2SO4 long (d), thu c dung dch Z v 1,12 lt kh H2(ktc). Nh t t dung dch Cu(NO3)2 0,5M vo dung dch Z cho ti khi ngng kh NO thot ra th dng li. Th tch dung dch Cu(NO3)2 dng lA. 158,3 ml. B. 140,0 ml. C. 100,0 ml.D. 160,5 ml.Hng dnTa c: FeO+ Fe2O3 Fe3O40,10,1 0,1Hn hp X coi nh gm: 0,2 mol Fe3O4; 0,1 mol Fe+ dung dch Y:Fe3O4 +8H+ Fe2+ +2Fe3++4H2O (1)0,20,2 0,4Fe+2H+Fe2++ H2

(2) 0,050,050,05Dung dch Zcha Fe2+ (0,35 mol), Fe3+ (0,35 mol), H+ d, Cl, SO 24.Nh t t dung dch Cu(NO3)2 vo dung dch Z : 3Fe2+ + NO3+4H+ 3Fe3++ NO+ 2H2O(3)73 0,35

0,353

3 23 33 2Cu(NO )NO NOCu(NO )0, 35 1n (mol) n n 0, 05 mol3 20, 05V 0,1(lit)0, 5 Bi 5. Cho 12,15 g bt Al vo 100 ml dung dch hn hp NaNO3 1,5M v NaOH 3M, khuy u cho n khi ngng kh thot ra th dng li. Th tch kh thot ra ktc lA. 5,04 ltB. 7,56 ltC. 6,72 ltD. 4,48 ltHng dnnAl = 0,45 (mol) ; 33NaNONOn n 0,15 mol ;OHn = nNaOH = 0,3 mol3 2 4 38Al 3NO 5OH 18H O 8[Al(OH) ] 3NH (1): 0, 45 0,15 0, 3: 0, 4 0,15 0, 25 0, 4 0,15: 0, 05 0 0, 05Ban uPhn ngD + + + +2 4 22Al 2OH 6H O 2 Al(OH) 3H (2): 0, 05 0, 05Ph : 0, 05 0, 05 0, 075D : 0 0[ ]Ban un ng + + +(1) v (2)nKh =0,15 + 0,075 = 0,225 (mol)Vkh = 0,225.22,4 = 5,04 (lt)Bi 6.Cho 6,4 g Cu tc dng vi 60 ml dung dch hn hp gm HNO32M v H2SO41M, thu c V lt kh NO duy nht (ktc), phn ng xy ra hon ton. Gi tr ca V lA. 0,672 B. 0,89674C. 1,344 D. 2,24Hng dnnCu= 0,1 mol; 3HNOn 0,12 mol ; 2 4H SO2n 0, 06.1 0, 06 (mol) Hn 0,12 2.0, 06 0, 24 (mol)+ + 3Cu+ 2NO3 +8H+

3Cu2+ +2NO +4H2OBan u : 0,10,12 0,24 Phn ng : 0,090,06 0,24 0,06D : 0,010,060 VNO = 0,06.22,4 = 1,344 (lt) Bi 7.DungdchAthtch200ml changthi hai mui MgCl20,4Mv Cu(NO3)20,2M. DungdchBchangthi KOH0,16MvBa(OH)2 0,02M. Th tch dung dch B cn lm kt ta ht hai ion Mg2+, Cu2+ lA. 1 lt B. 1,2 ltC. 1,5 lt D. 1,7 ltHng dnS phn ng 2 23 2 2 2 2MgCl KOH Mg(OH) KCl(I)Cu(NO ) Ba(OH) Cu(OH) BaCl+ +Phng trnh ion thu gn2222Mg Mg(OH)OH (II)Cu Cu(OH)+++ -t(+)OHt(+) t(-)n 2.0,08 2.0,04 0,24(mol)n V.0,16 V.0,04 0,2V(mol)n n 0,24 0,2V V 1,2(lt) + + 75Bi 8.Cho 3,75g hn hp A gm Mg v Al vo 250 ml dung dch X cha axit HCl1M vH2SO40,5M, c dung dch B v 3,92 lt H2(ktc).Thnh phn % khi lng Mg, Al trong A lA. 65% ; 35%. B. 64% ; 36%.B. 55% ; 45%. D. 50% ; 50%.Hng dn2Mg AlHH2n x(mol) ; n y(mol)24x 27y 3,75 (1)3,92n 0,25 0,25 0,5(mol) ; n 0,175(mol)22,42H 2e H0,35 0,175++ + + + Vy axit d : p dng LBT e ta c 2x+3y= 0,35 (2)T (1), (2) x 0,1(mol) ; y 0,05(mol) MgAl24.0,1.100%m 64%3,75%m 36% 'Bi 9. Cho hn hp A gm Mg v Al vo 500 ml dung dch X cha axit HCl 1M v H2SO4 0,5M, c dung dch B v 3,92 lt H2 (ktc). Th tch dung dch C gm NaOH0,2MvBa(OH)20,1M cn phn ng ht vi cccht trong B l A. 0,125 lt B. 1,112 ltC. 1,875 lt D. 1,235 ltHng dn762HH2H (d )OH3,92n 0,5.1 0,5.0,5 0,75(mol) ; n 0,175(mol)22,42H 2e H0,35 0,175n 0,75 0,35 0,4(mol)n 0,2V 2.0,1V 0,4V(mol)+++ + + + 22332Mg 2OH Mg(OH)Al 3OH Al(OH)H OH H O+ + + + + + Trong B :2 3dt( )Mg Al Hn 2n 3n n H 0,75(mol)+ + +++ + + Trong C :dt( )OHn n 0,4V Mi trng trung tnh khi 0,4V =0,75 V = 1,875(lt).Bi 10. Ho tan hon ton mg hn hp X gm 2 kim loi kim A, B v kim loi kim th M vo nc thu c dung dch C v 5,6 lt kh H2 (ktc). Dung dch D gm H2SO4 0,1M v HCl 0,3M. trung ho dung dch C cn s lt dung dch D lA. 0,5 lt B. 1,5ltC. 1,5 lt D. 2 ltHng dn2H5,6n 0,25(mol)2,4 Kim loi kim kh nc gii phng H2, na phn ng nc b oxi ho sau 2 22H O 2e H 2OH0,25 0,5+ +Khi mi trng trung tnh th H OHn n 0,2V 0,3V 0,5 V 1lit+ + 77Bi 11. Ha tan hon ton 9,65 g hn hp 2 kim loi Fe, Al trong dung dch hn hp HCl v H2SO4long,kt thc phn ng thu c 7,28 lt H2(ktc). Phn trm khi lng ca st trong hn hp ban u lA. 50,32%.B. 35,53%. C.51,81 %. D. 56,48%.Hng dn2Hn= 0,325 mol ; t x, y ln lt l s mol ca Al, Fe cha trong hn hp. Ta c: 27x + 56y=9,65(I)Phng trnh ion rt gn ca cc phn ng2Al + 6H+ 2Al3++ 3H2(1)x 1,5x Fe+2H+ Fe2+ + H2 (2) y yT (1) v (2) 2HV= 1,5 x+y= 0,325 y = 0,325 1,5x (II)T (I) v (II) ta tnh c : x = 0,15 mol ; y = 0,1 mol%mAl = 0,15.27.100% 41,19%9, 65 %Fe = 100 41,19 =58,81% Bi 12.Cho m g hn hp Mg, Al vo 250 ml dung dch X cha hn hp axitHCl 1 M v axit H2SO4 0,5 M, thu c 5,32 lt H2 ( ktc) v dung dch Y (coi th tch dung dch khng i). Dung dch Y c pH lA. 7 B. 1C. 2 D. 6Bi 13. Dung dch A cha NaOH 1 M v Ca(OH)2 0,01 M. Sc 2,24 lt kh CO2 vo 400 ml dung dch A ta thu c mt kt ta c khi lng lA. 1,5g B. 10gC. 4g D. 0,4g786.Phng php xc nh cng thc cht ho hcC sDng 1. Tm Z (in tch ht nhn) ca nguyn t . Dng 2.Tm c M (nguyn t khi) ca nguyn t . Bit ho tr ca nguyn t cn tm ta ch cn xc nh nguyn t khi ca nguyn t . Khng bit ho tr ca nguyn t cn tm, ta phi lp c biu thc lin h gia M v ho tr n ca nguyn t :M = k.nxcnhcngthccamt hpcht davonhlut thnhphn khng i. Xc nh cng thc ho hc ca mt hp cht.+ Nu bit cc nguyn t thnh phn cu to nn cht AxByCx, ta ch vic xc nh x, y, z hoc x : y : z suy ra cng thc phn t (v i vi hp cht v c th cng thc thc nghim thng trng vi cng thc phn t).+Nuchabit mt nguyntthnhphnnoth taphi xcnh nguyn t khi ca nguyn t v ho tr tng ng ca n.+ Nu bi ton yu cu xc nh cng thc ca oxit kim loi m kim loi c ho tr khng i, ta t CT ca oxit kim loi l M2On. Trng hp khc ta phi t cng thc ca oxit dng MxOy. T tm cng thc thc nghim v xc nh cng thc phn t.Bi tp minh hoBi 1. Tng s ht proton, ntron v electron trong nguyn t ca nguyn t X l 22. Nguyn t X lA. N B. OC. F D. ClLi gii. a)Theo gi thit : 2Z + N = 22 N = 22 - 2Z79Mt khc ng v bn c : N1 1, 5Z 22 2Z1Z22 2Z1, 5Z'6,2 Z7,3V Z phi l nguyn dng nn chn gi tr Z = 7. Vy X l NitBi 2. Tng s cc ht proton, ntron v electron trong nguyn t ca nguyn t X thuc nhm VA ca bng tun hon l 47. Nguyn t X l A. Si B. P C. Cl D. SLi giiTheo gi thuyt ta c : 2Z + N = 47 N = 47 2Z Ta c :47 2Z1 1, 5Z 13,4 Z 15,6 Z phi nguyn dng nn Z c th l : Z = 14 hoc Z = 15 Nu Z = 14 c cu hnh electron nguyn t : 1s22s22p63s23p2 X thuc nhm IVA (Loi, v tri vi u bi) Nu Z = 15 c cu hnh electron nguyn t : 1s22s22p63s23p3. X thuc nhm VA vy X l photpho (P)Bi 3. Ha tan hon ton mt kim loi (ha tr 3) trong 100 ml dung dch H2SO4 1M. trung ha lng axit d phi dng ht 20 ml dung dch NaOH 1M. Dung dch thu c cho tc dng vi dung dch NH3d, lc kt ta, em nung n khi lng khng i thu c 3,06 g cht rn. Kim loi lA. B B. AlC. Cr D. GaLi gii Gi kim loi cn tm l A.80o2 32 4 2 4 3 22 4 2 4 22 4 3 3 2 3 4 2 4t3 2 3 2A O A A2A 3H SO A (SO ) 3H0,09 0,03H SO 2NaOH Na SO 2H O0,01 0,02A (SO ) 6NH 6H O 2A(OH) 3(NH ) SO0,03 0,062A(OH) A O 3H O0,06 0,033,06M 2M 48 102 M 27: AlAl0,03+ ++ ++ + + + + Bi 4. Ho tan 1,2 g mt kim loi ho tr II bng mt hn hp gm 40ml dung dch H2SO4 1M v 200ml HCl 0,2M. Dung dch thu c c tnh axt, trung ho dung dch ny phi dng100ml dung dch NaOH 0,2M. Kim loi l A. Mg B. FeC. Zn D. CaLi giiHOH2n 0,04.2.1 0,2.0,2 0,12(mol)n 0,02(mol)H OH H O++ + + S mol H+ phn ng vi kim loi l 0,1 (mol)22MM 2H M H0,05 0,11,2M 24 vy M lMg0,05+ ++ + Bi 5.Cho 3,78g bt Al tc dng va vi XCl3thy to thnh dung dch Y. Khi lng cht tan trong dung dch Y gim 4,06g so vi dung dch XCl3. Cng thc ca mui l81A. PCl3B. FeCl3C. CrCl3D. AuCl3Li gii3+ 3+X XAl + XAl + XM27 M=M 27 gim khi lng thc ca 3,870,14(mol)27 Al lm = 0,14(MX 27) = 4,06 MX = 56 ; X l Fe.Bi 6. Ho tan 3,12 g hn hp A gm FeSO4 v XSO4 (c s mol bng nhau) vo nc thu c 100 ml dung dch A. Cho lng A trn tc dng vi dung dch BaCl2 d thu c 4,66 g kt ta v dung dch B. X l nguyn t no sau y ?A. Zn B. CuC. Ca D. BaLi gii 4 22 44 2FeSO FeClBaCl BaSOXSO XCl+ + chnh lch khi lng ca 1 mol A BaSO4: M= 2.137 56 MX = 218 MXVi s mol FeSO4=XSO4=1 4,66. 0,01(mol)2 233 th chnh lch khi lngm = 0,01(218 MX ) = 4,66 3,12 =1,54 MX = 64 : CuBi 7.Ho tan 9,6 g mt kim loi A trong dung dch HNO3 d, thu c dung dch cha mt mui B v 2,24 lt kh NO (ktc). Kim loi lA. Cu B. PbC. ZnD. Fe82Li giit s mol v ho tr ca A ln lt l x v n3A+ 4nHNO33A(NO3)n + nNO +2nH2ONOA3.n 3.0,1 9,6nx ; M 32nn n 0,3 gi tr ph hp n = 2 v MA = 64 : CuBi 8. Ho tan hon ton 5,3g mui cacbonat ca mt kim loi kim R2CO3 trong 500ml dung dch HCl 0,1M, H2SO4 0,2M. Sau phn ng thu c dung dch X v th tch kh thot ra l V = 1,12 lt (ktc). R l nguyn t no sau y ?A. Na B. KC. Li D. CsLi giiBn cht cc phn ng l 23CO+2H+ 2CO+H2O0,05 0,1 0,05R R5,32M 60 106 M 230,05+ ; M l Na.Bi 9. Ho tan va hn hp gm kim loi M v oxit MO (M c ho tr khng i v MO khngphil oxit lng tnh) trong dung dch HNO3d thu c dung dch A v kh NO. Cho A tc dng va vi 240ml dung dch NaOH 0,5M thu c kt ta. Lc thu kt ta ri nung ti khi lng khng i c 2,4g cht rn. M l nguyn t no sau y ?A. Ca B. CuC. Ba D. MgLi giiNaOHn 0,12mol . S phn ng :832+3 2MHNO ... M+ 2OHM(OH)MOMO 0,12 0,06+ + Theo nh lut bo ton in tch : 2M OH1n n 0,06(mol)2+ MM + 16 =M2,4M 240,06 ; M l Mg.Bi 10. Ho tan 32g kim loi M trong dung dch HNO3 d thu 8,96 lt hn hp hai kh (ktc) NO v N2O4 c t khi hi so vi khng kh l 1,34 v dung dch X. Kim loi M lA. Zn B. MgC. CuD. AlLi gii3 3 2 22 4NOM HNO M(NO ) H ON O+ + +2 4NON Oa b 0,4a n 0,3mol30a 92bb n 0,05mol 34a b+ +' ' +Cc bn phn ng :n +5 +25 42 4M M ne N + 3eN (NO)11 0,9 0,3 0,03nN e N (N O )0,1 0,1 0,05++ + + +

32nM 32n1 . Gi tr ph hp n = 2 thMM 64(Cu) .84Bi tp vn dngBi 1. Ho tan hon ton 2,16g mt oxit kim loi A trong dung dch HNO3 long, thu c dung dch B (khng cha mui amoni) v 0,224 lt kh NO (ktc). Cng thc ca oxit kim loi lA. CuO B. FeOC. Fe3O4D. CrOHng dnt cng thc ca oxit MxOy ta c s phn ng x y 3 3 a 2M O HNO M(NO ) NO H O + + +x y x y2ya 5 2xM O M OCht cho echt nhn e2yM M (a ) N 3e Nx0,03 0,03 0,010,03 0,03n m (x.M 16y) 2,16ax-2y ax-2y2,16ax 4,8y 2yM 72a 160y (a )0,03x x++ + + + + + >

Gi tr ph hp a=3 ; y = 1; M = 56; x = 1 vy cng thc ca oxit :FeOBi 2.Cho mt lung kh CO i qua 16g mt oxit st nguyn cht nung nng trong ng s. Sau khi phn ng kh ht oxit ta thy khi lng chtrn gim 4,8g. Cng thc ca oxit st lA. FeO B. Fe2O3C. Fe3O4D. 2FeO. Fe2O3Hng dnFexOy+CO Fe+CO2Fe16 4,8n 0,256 mol ; O4,8n 0,316 molx : y = nFe : nO = 0,2 : 0,3 = 2 : 3 Cng thc ca oxit l 2 3Fe O85Bi 3. Hp cht A c cng thc MxSy (M l kim loi). t chy hon ton A thu c oxit MnOm v kh B. Dn B vo dung dch cha Br2 v Ba(NO3)2 d thy to thnh 69,9 g kt ta. Mt khc, kh hon ton MnOm bng CO d thu c 8,4 g kim loi. Ho tan hon ton lng kim loi ni trn bng dung dch HNO3 long thu c mui M3+ v 3,36 lt (ktc) kh NO. Cng thc phn tca A lA. FeS B. CuS. C. FeS2 D. Cu2SHng dn22 2 2O Br H O Ba 2x y 2 4 4M S ... SO SO BaSO++ + Theo s bo ton nguyn t S :x y 4S(M S ) S(BaSO )69,9n n 0,3(mol)233 3 3 3 2M FeFe S 2M 4HNO M(NO ) NO H O0,15 0,158,4M 56(Fe) n 0,15mol0,15x : y n : n 0,15: 0,3 1: 2 A : FeS+ + + Bi 4. A l hn hp dng bt gm Fe v kim loi M (c ho tr khng i). Cho 8,64g hn hp A tc dng va vi 80ml dung dch CuSO41,5M. Mt khc ly mt lng A ng nh trn ho tan ht trong dung dch HNO3 thu c 3,136 lt kh NO duy nht ktc (khng c NH4NO3). M l nguyn t no sau y ?A. Zn B. AlC. Cu D. AgHng dnnFe = x (mol); nM = y (mol)Nu M y c Cu ra khi dung dch :8622nFe FeCu CuM M++++ +p dng s bo ton electron, ta c :2x + ny = 2.0,12 = 0,24 (mol)(1)Trong phn ng vi HNO3 :3 33 23 nFe Fe(NO )HNO NO H OM M(NO )+ + +3x + ny = 3.3,1360,4222,4 (mol)(2)Gii h (1) v (2). H ny v nghim. Vy M khng y c Cu.Fe+ Cu2+ Fe2++Cux = 0,12 ny = 0,06mM = 1,92 MM = 1,92.n32n M:Cu0,06 Bi 5. Ho tan 3,06g ho hc Na2CO3v MCO3(t l 2 3 3Na CO MCOn : n 1: 2 ) trong H2SO4long d, kh thu c hp th hon ton trong 100ml dung dch Ca(OH)2 0,2M thu c 1,97g kt ta. Kim loi M lA. Ba B. CaC. Zn D. CuHng dn2 3 2 42 4 2 23 4Na CO Na SOx H SO x CO H OMCO MSOy y+ + +872 2 3 22 2 3 2CO Ba(OH) BaCO H O0,01 0,01 0,012CO Ba(OH) Ba(HCO )0,02 0,01+ ++ x = 0,01 (mol) ; y = 0,02 (mol)0,01.106 + 0,02.(M + 60) = 3,06 M = 40 : CaBi 6. Mt hn hp X gm hai hirocacbon A, B c khi lng a g. Nu t chyhon ton X th thu c 132a/41 g CO2 v 45a/41 g H2O. Nu thm vo Xmt na lng A c trong X ri mi em t chy hon ton th thu c165a/41 g CO2 v 60,75g H2O. CTPT ca A, B lA. C5H12 ; C5H10B. C6H14 ; C6H6C. C6H12; C6H10D. C7H14 ; C7H16Li giiVi mi a tu ta u tm c kt qu bi ton: Chn a = 41 g2CO(165 132).2n 1,5(mol)44 2H O(60,75 45).2n 1,75(mol)18 V 2 2H O COn n >A l ankanCnH2n+2 nCO2 + (n+1)H2O n = 6 Vy A: C6H14Khi Bchy:2 2CO H On 1,5(mol) n 0,75(mol) < BkhngthlAnkan hoc Anken, B khng lm mt mu dung dch Br2 Nn B l aren. Vit phn ng chy xc nh c 6 6C H. Bi 7. t chy hon ton m g cht hu c A cha C, H, O thu c 22m15g CO2 v 3m5g H2O. Bit rng 3,6g hi A c th tch bng th tch ca 1,76g CO2 88cng iu kin. CTPT A l:A: C2H6O2B: C3H6O3C: C3H4O3D: C2H4O2Hng dnVi mi m ta u xc nh c CTPT ca A, chn m = 15 g.22C(A) COH(A) H O OC H O 2 n3 6 3n n 0,5(mol)9 15 0,5.12 1n 2n 2. 1(mol);n 0,5(mol)18 163,6n : n : n 1:2:1 (CH O) 90 n 30,04CTPT :C H O + 7. Phng php gii cc bi ton cc i - cc tiu Cch tm khong gii hn ca mui : Hn hp kim loi (A, B) tc dng vi hn hp axit (HNO3 v H2SO4) to ra hn hp mui sunfat v mui nitrat.+) Do 1 mol24SO(nng 96 gam) tng ng vi 2 mol3NO(nng 124 gam). Vi cng mt hn hp kim loi nu to mui nitrat th khi lng s nng hn mui sunfat. Khi lng mui cc i khi hn hp ch to ra mui nitrat v cc tiu khi hn hp ch to mui sunfat. Vy khi lng thc t l 2- -4 3thc tmui SO mui NOm m m