Chapter 5, Problem 5.59E

A sample of calcium metal with a mass of $2.00\text{g}$ was reacted with excess oxygen. The following equation represents the reaction that took place:

$2\text{Ca}\left(\text{s}\right)+{\text{O}}_{\text{2}}\left(\text{g}\right)\to 2\text{CaO}\left(\text{s}\right)$

The isolated product $\left(\text{CaO}\right)$ weighed $2.26\text{g}$. What was the percentage yield of the

reaction?