Mass–mass calculations Knowledge-Based Download PDF

Questions

1. 1.

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

   • A) 25.5 g
   • B) 51.0 g
   • C) 76.5 g
   • D) 102.0 g
2. 2.

   According to the balanced chemical equation $2\text{KClO}_3\text{(s)} \rightarrow 2\text{KCl(s)} + 3\text{O}_2\text{(g)}$, what mass of oxygen gas ($\text{O}_2$) is produced by the complete decomposition of 24.5 g of potassium chlorate ($\text{KClO}_3$)? (Molar masses: $\text{K} = 39.0\text{ g/mol}$, $\text{Cl} = 35.5\text{ g/mol}$, $\text{O} = 16.0\text{ g/mol}$)

   • A) 4.27 g
   • B) 4.80 g
   • C) 9.60 g
   • D) 6.40 g
3. 3.

   According to the balanced equation $\text{Fe}_2\text{O}_3\text{(s)} + 3\text{CO(g)} \rightarrow 2\text{Fe(s)} + 3\text{CO}_2\text{(g)}$, what mass of iron is produced from the complete reaction of 80.0 g of iron(III) oxide? (Molar masses: $\text{Fe} = 56.0\text{ g/mol}$, $\text{O} = 16.0\text{ g/mol}$, $\text{C} = 12.0\text{ g/mol}$)

   • A) 56.0 g
   • B) 28.0 g
   • C) 112.0 g
   • D) 40.0 g
4. 4.

   According to the balanced equation $4\text{Al(s)} + 3\text{O}_2\text{(g)} \rightarrow 2\text{Al}_2\text{O}_3\text{(s)}$, what mass of oxygen gas is required to react completely with 54.0 g of aluminum? (Molar masses: $\text{Al} = 27.0\text{ g/mol}$, $\text{O} = 16.0\text{ g/mol}$)

   • A) 48.0 g
   • B) 64.0 g
   • C) 40.5 g
   • D) 24.0 g
5. 5.

   According to the balanced equation $\text{C}_3\text{H}_8\text{(g)} + 5\text{O}_2\text{(g)} \rightarrow 3\text{CO}_2\text{(g)} + 4\text{H}_2\text{O(g)}$, what mass of water is produced by the complete combustion of 22.0 g of propane ($\text{C}_3\text{H}_8$)? (Molar masses: $\text{H} = 1.0\text{ g/mol}$, $\text{C} = 12.0\text{ g/mol}$, $\text{O} = 16.0\text{ g/mol}$)

   • A) 9.0 g
   • B) 27.0 g
   • C) 36.0 g
   • D) 66.0 g