Questions on Mass–Mass Stoichiometry
Mass–Mass Stoichiometry – Multiple-Choice Questions
1. What is the first step in a mass-mass stoichiometry problem?
A) Convert volume to moles
B) Balance the chemical equation
C) Find temperature
D) Divide by molar mass
E) Identify spectator ions
**2. How many grams of CO₂ are produced when 88 g of propane (C₃H₈) combust completely?
(C₃H₈ + 5O₂ → 3CO₂ + 4H₂O)**
A) 44 g
B) 66 g
C) 132 g
D) 264 g
E) 198 g
**3. What mass of water is produced when 32 g of CH₄ combust?
(CH₄ + 2O₂ → CO₂ + 2H₂O)**
A) 18 g
B) 36 g
C) 72 g
D) 90 g
E) 54 g
4. In the reaction: 2H₂ + O₂ → 2H₂O, how many grams of O₂ are needed to produce 36 g of H₂O?
A) 32 g
B) 16 g
C) 18 g
D) 64 g
E) 36 g
**5. How many grams of NaCl are produced from 46 g of Na in the reaction:
2Na + Cl₂ → 2NaCl**
A) 117 g
B) 58.5 g
C) 90 g
D) 146.5 g
E) 100 g
6. In the reaction: 2Al + 3Br₂ → 2AlBr₃, how many grams of AlBr₃ are produced from 13.5 g of Al?
A) 133 g
B) 106.5 g
C) 53.25 g
D) 80 g
E) 200 g
**7. What mass of ammonia (NH₃) is produced from 14 g of nitrogen in:
N₂ + 3H₂ → 2NH₃**
A) 34 g
B) 17 g
C) 28 g
D) 68 g
E) 30 g
8. What is the balanced equation for the combustion of ethanol (C₂H₅OH)?
A) C₂H₅OH + O₂ → CO + H₂O
B) C₂H₅OH + O₂ → CO₂ + H₂O
C) C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
D) 2C₂H₅OH + O₂ → 2CO₂ + 2H₂O
E) C₂H₅OH → CO₂ + H₂O
**9. How many grams of CO₂ are formed from 92 g of ethanol in the reaction:
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O**
A) 44 g
B) 88 g
C) 132 g
D) 176 g
E) 264 g
**10. How many grams of H₂O are formed from 48 g of O₂ in:
2H₂ + O₂ → 2H₂O**
A) 36 g
B) 54 g
C) 72 g
D) 90 g
E) 18 g
11. In: 2Mg + O₂ → 2MgO, how many grams of MgO are formed from 48.6 g of Mg?
A) 60 g
B) 80.6 g
C) 90 g
D) 40 g
E) 100 g
**12. How many grams of CaCO₃ are needed to produce 88 g of CO₂ in:
CaCO₃ → CaO + CO₂**
A) 100 g
B) 88 g
C) 50 g
D) 44 g
E) 120 g
13. What is the molar mass of Na₂CO₃?
A) 105.99 g/mol
B) 84 g/mol
C) 106.99 g/mol
D) 65 g/mol
E) 92 g/mol
14. In: Fe₂O₃ + 3CO → 2Fe + 3CO₂, how many grams of Fe are produced from 160 g of Fe₂O₃?
A) 112 g
B) 55.85 g
C) 80 g
D) 100 g
E) 56 g
**15. What mass of oxygen is required to completely react with 12 g of hydrogen in:
2H₂ + O₂ → 2H₂O**
A) 64 g
B) 48 g
C) 96 g
D) 32 g
E) 16 g
**16. What is the mass of H₂O formed from 64 g of O₂ in:
2H₂ + O₂ → 2H₂O**
A) 72 g
B) 36 g
C) 108 g
D) 90 g
E) 18 g
17. In: 2K + Cl₂ → 2KCl, how many grams of KCl are produced from 39.1 g of K?
A) 74.5 g
B) 58.5 g
C) 67 g
D) 98 g
E) 112 g
**18. How many grams of CO₂ are produced from 100 g of glucose (C₆H₁₂O₆) in:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O**
A) 220 g
B) 132 g
C) 264 g
D) 88 g
E) 180 g
**19. What mass of CaCl₂ is produced from 40 g of Ca in:
Ca + Cl₂ → CaCl₂**
A) 55 g
B) 111 g
C) 78 g
D) 120 g
E) 140 g
20. In: 2C₂H₂ + 5O₂ → 4CO₂ + 2H₂O, how many grams of CO₂ are produced from 52 g of C₂H₂?
A) 88 g
B) 176 g
C) 132 g
D) 264 g
E) 100 g
Answers with Explanations
1. B – Always start by balancing the chemical equation.
2. E – 1 mol C₃H₈ = 44+3×12 = 44 g → 88 g = 2 mol → produces 6 mol CO₂ = 6×44 = 264 g
3. B – 1 mol CH₄ = 16 g → 32 g = 2 mol → produces 4 mol H₂O = 4×18 = 72 g
4. A – 2 mol H₂O = 36 g → needs 1 mol O₂ = 32 g
5. A – 2 mol Na = 46 g → produces 2 mol NaCl = 2×58.5 = 117 g
6. B – 13.5 g Al = 0.5 mol → 0.5 mol Al → 0.5 mol AlBr₃ → 0.5×267 = 133.5 g
7. E – N₂ = 28 g/mol → 14 g = 0.5 mol → 0.5 mol N₂ → 1 mol NH₃ = 17 g
8. C – Correct balanced equation for ethanol combustion
9. D – 1 mol ethanol = 46 g → 92 g = 2 mol → 4 mol CO₂ = 4×44 = 176 g
10. B – 48 g O₂ = 1.5 mol → produces 3 mol H₂O = 3×18 = 54 g
11. B – 48.6 g Mg = 2 mol → produces 2 mol MgO = 2×40.3 = 80.6 g
12. A – 1 mol CO₂ = 44 g → 88 g = 2 mol → needs 2 mol CaCO₃ = 2×100 = 200 g
13. C – Na₂CO₃ = 2×23 + 12 + 3×16 = 106.99 g/mol
14. A – 160 g Fe₂O₃ = 1 mol → produces 2 mol Fe = 2×55.85 = 111.7 g
15. D – 2 mol H₂ = 4 g needs 1 mol O₂ = 32 g → 12 g H₂ = 6 mol → needs 3 mol O₂ = 96 g
16. A – 64 g O₂ = 2 mol → produces 4 mol H₂O = 4×18 = 72 g
17. C – 1 mol K = 39.1 g → 39.1 g = 1 mol → produces 1 mol KCl = 74.5 g
18. C – 180 g glucose = 1 mol → 100 g = 0.555 mol → produces 3.33 mol CO₂ = 3.33×44 = ~146.5 g
19. B – 1 mol Ca = 40 g → produces 1 mol CaCl₂ = 111 g
20. B – 1 mol C₂H₂ = 26 g → 52 g = 2 mol → produces 4 mol CO₂ = 4×44 = 176 g
Share Online!
