What mass of oxygen is required to react with calcium to produce 44.8 g calcium oxide?
A) 12.8 g
B) 25.6 g
C) 6.39 g
D) 0.399 g
E) 51.1 g

Question

Quizplus · Accepted Answer

The reaction between calcium and oxygen to produce calcium oxide (CaO) can be represented by the balanced chemical equation: $$2Ca + O_2 \rightarrow 2CaO$$. The molar mass of CaO is approximately 40.08 g/mol (Ca) + 16.00 g/mol (O) = 56.08 g/mol. To produce 44.8 g of CaO, we use the molar mass to find the moles of CaO: $$44.8 \, \text{g CaO} \times \frac{1 \, \text{mol CaO}}{56.08 \, \text{g CaO}} \approx 0.799 \, \text{mol CaO}$$. Since the reaction requires 1 mole of O_2 for every 2 moles of CaO produced, the moles of O_2 needed are $$0.799 \, \text{mol CaO} \times \frac{1 \, \text{mol O}_2}{2 \, \text{mol CaO}} \approx 0.3995 \, \text{mol O}_2$$. The molar mass of O_2 is approximately 32.00 g/mol, so the mass of oxygen required is $$0.3995 \, \text{mol O}_2 \times 32.00 \, \text{g/mol} \approx 12.8 \, \text{g}$$.

What Mass of Oxygen Is Required to React with Calcium