Chapter 10, Problem 89RQ

A 0.200 mol sample of a mixture of ${\text{N}}_{\text{2}}$ and ${\text{CO}}_{\text{2}}$ with a total pressure of 845 torr was exposed to an excess of solid CaO, which reacts with ${\text{CO}}_{\text{2}}$ according to the equation

$\text{CaO}\left(s\right){\text{ + CO}}_{\text{2}}\left(g\right)\stackrel{}{\to }{\text{CaCO}}_{\text{3}}\left(s\right)$

After the reaction was complete, the pressure of the gas had dropped to 322 torr. How many moles of ${\text{CO}}_{\text{2}}$ were in the original mixture? (Assume no change in volume or temperature.)