Mass–mass calculations Knowledge-Based Practice

Questions

1. 1.

   According to the balanced equation $\text{Fe}_2\text{O}_3(s) + 3\text{CO}(g) \rightarrow 2\text{Fe}(s) + 3\text{CO}_2(g)$, what mass of iron(III) oxide is required to produce 11.2 g of iron in the presence of excess carbon monoxide? (Molar masses: $\text{Fe} = 56.0\text{ g/mol}$, $\text{C} = 12.0\text{ g/mol}$, $\text{O} = 16.0\text{ g/mol}$)

   • A) 64.0 g
   • B) 32.0 g
   • C) 8.0 g
   • D) 16.0 g
2. 2.

   According to the balanced equation $2\text{KClO}_3(s) \rightarrow 2\text{KCl}(s) + 3\text{O}_2(g)$, what mass of potassium chlorate ($\text{KClO}_3$) must decompose completely to produce 48.0 g of oxygen gas? (Molar masses: $\text{K} = 39.1\text{ g/mol}$, $\text{Cl} = 35.5\text{ g/mol}$, $\text{O} = 16.0\text{ g/mol}$)

   • A) 275.9 g
   • B) 183.9 g
   • C) 245.2 g
   • D) 122.6 g
3. 3.

   According to the balanced equation $\text{N}_2(g) + 3\text{H}_2(g) \rightarrow 2\text{NH}_3(g)$, what mass of ammonia ($\text{NH}_3$) is produced by the complete reaction of 42.0 g of nitrogen gas with excess hydrogen gas? (Molar masses: $\text{H} = 1.0\text{ g/mol}$, $\text{N} = 14.0\text{ g/mol}$)

   • A) 51.0 g
   • B) 25.5 g
   • C) 102.0 g
   • D) 12.8 g
4. 4.

   According to the balanced equation $\text{CaCO}_3(s) \rightarrow \text{CaO}(s) + \text{CO}_2(g)$, what mass of calcium oxide ($\text{CaO}$) is produced by the complete thermal decomposition of 50.0 g of calcium carbonate ($\text{CaCO}_3$)? (Molar masses: $\text{Ca} = 40.0\text{ g/mol}$, $\text{C} = 12.0\text{ g/mol}$, $\text{O} = 16.0\text{ g/mol}$)

   • A) 28.0 g
   • B) 56.0 g
   • C) 22.0 g
   • D) 14.0 g
5. 5.

   According to the balanced equation $\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}$, what mass of water is produced by the complete combustion of 32.0 g of methane in excess oxygen? (Molar masses: $\text{H} = 1.0\text{ g/mol}$, $\text{C} = 12.0\text{ g/mol}$, $\text{O} = 16.0\text{ g/mol}$)

   • A) 18.0 g
   • B) 36.0 g
   • C) 72.0 g
   • D) 88.0 g

Answers and step-by-step solutions appear after you finish the test.