University:
Winston-Salem Forsyth County Schools
Course:
AP Chemistry
Academic year:

2014
Views:

44

Pages:

4
Author:

Ariel Coleman

MASS – MASS STOICHIOMETRY 1. How many grams of zinc are needed to react with HCl in order to produce 25.2 g of ZnCl2? Zn + 2HCl  ZnCl2 + H2 unknown given (25.2 g) MM of ZnCl2  25.2 g ZnCl2 1 136.30 g 1 mol Molar mass of Zn  65.39 g 1 mol 1 mol ZnCl2 136.30 g ZnCl2 1 mol Zn 65.39 g Zn 1 mol ZnCl2 1 mol Zn Answer  12.1 g of Zn 2. 45.6 g of K2O reacts with excess AlCl3. How much KCl can be produced by this reaction? 3K2O + 2AlCl3  6KCl + Al2O3 given unknown (45.6 g) molarMass of K2O  94.1960 g MM of KCl  74.551 g 1 mol 1 mol 45.6 g K2O 1 mol K2O 6 mol KCl 74.551 g KCl 1 94.1960 g K2O 3 mol K2O 1 mol KCl Answer  72.2 g of KCl 3. How much CuSO4 is needed to react completely with 12.01 g of Ag? CuSO4 + 2Ag  Ag2SO4 + Cu Unknown given (12.01 g) MM of Ag  107.9 g MM of CuSO4  159.610 g 1 mol 1 mol 12.01 g Ag 1 1 mol Ag 107.9 1 mol CuSO4 g Ag Answer  8.885 g of CuSO4 2 mol Ag 159.610 g CuSO4 1 mol CuSO4 4. 65.1g of C2H6 can be burned in the presence of O2 and produce how much H2O? 2C2H6 + 7O2  4CO2 + 6H2O given unknown (65.1 g) M-M of C2H6  30.1 g 1 mol 65.1 g C2H6 1 MM of H2O  18.0 g 1 mol 1 mol C2H6 6 mol H2O 18.0 g H2O 30.1 g C2H6 2 mol C2H6 1 mol H2O Answer  117 g of H2O 5. How much CaO is needed to react with H2O in order to synthesize 471g of Ca(OH)2? CaO + H2O  Ca(OH)2 unknown given (471 g) MM of Ca(OH)2  74.1 g 1 mol 471 g Ca(OH)2 1 MM of CaO  56.1 g 1 mol 1 mol Ca(OH)2 74.1 g Ca(OH)2 1 mol CaO 1 mol Ca(OH)2 56.1 g CaO 1 mol CaO Answer  356.6 g of CaO 6. Water can be decomposed into hydrogen gas and oxygen gas through electrolysis. 15.2 g of water, therefore could produce how much oxygen gas? 2H2O  2H2 + O2 given unknown (15.2 g) MM of H2O  18 g 1 mol MM of O2  32 g 15.2 g of H2O 1 mol H2O 1 18.0 g H2O Answer  13.5 g O2 1 mol 1 mol O2 2 mol H2O 32 g O2 1 mol O2 7. Excess Al2O3 reacts with 74.66 g of NaOH in order to produce how much Al(OH)3? Al2O3 + 6NaOH  2Al(OH)3 + 3Na2O Given unknown (74.66 g) MM of NaOH  74.66 g NaOH 1 40 g 1 mol MM Al(OH)3 1 mol NaOH 40 g NaOH  78.0 g 1 mol 2 mol Al(OH)3 78.0 g Al(OH)3 6 mol NaOH 1 mol Al(OH)3 Answer  48.53 g Al(OH)3 8. How many grams of KCN are needed to react completely with 1.45 g of CuS? 2KCN + CuS  K2S + Cu(CN)2 unknown given (1.45 g) MM of CuS  95.6 g 1 mol MM of KCN  1.45 g CuS 2 mol KCN 1 1 mol CuS 95.6g CuS 65.1 g 1 mol 65.1 g KCN 1 mol CuS 1 mol KCN Answer  1.98 g KCN 9. 1.23 g of NaOH can be neutralized by how much HCl? NaOH + HCl  NaCl + given unknown (1.23 g) MM of NaOH  40 g 1 mol 1.23 g NaOH 1 MM of HCl  36.5 g H2O 1 mol 1 mol NaOH 1 mol HCl 36.5 g HCl 40 1 mol NaOH 1 mol HCl g NaOH Answer  1.12 g HCl 10. FeCl3 reacts with 368 g of CaCO3 in order to produce how much CaCl2? 2FeCl3 + 3CaCO3  3CaCl2 + Fe2(CO3)3 given unknown (368 g) MM of CaCO3  100.1 g 1 mol 368 g CaCO3 1 mol 1 mol CaCO3 100.1 g CaCO3 Answer  408 g CaCl2 MM of CaCl2  111.0 g 1 mol 3 mol CaCl2 111.0 gCaCl2 3 mol CaCO3 1 mol CaCl2