Question

Suppose a container holds 1000 hydrogen molecules and 1000 oxygen molecules that react to form water. how many water molecules will be left in the container?

Answer 1

The reaction is:

$H_{2} + \frac{1}{2} O_{2} = H_{2}O$

From the equation, he limiting reactant is the oxygen. Assuming 100% yield, all of the oxygen must react to form water.

1000 mol $O_{2}$ * (1 mol $H_{2}O$ ÷ ½ mol $O_{2}$) = 2000 moles water produced