Question

2.8 g of calcium oxide prepared by heating limestone produced 0.8 g of oxygen. Calculate the mass percentage of calcium.

• A. $61.4\%$
• B. $91.2\%$
• C. $71.4\%$
• D. $81.6\%$

Answer 1

The correct option is C $71.4\%$

Formula of calcium oxide $\to$ CaO.
$Mass\%ofCa=\frac{2.8g-.8g}{2.8g}\times 100=\frac{60}{60+360}\times 100=14.28\%$