# The volume of a gas at 155 kPa changes from 22.0 L to 10.0 L. What is the new pressure if the temperature remains constant?

Approx. $320 \cdot k P a$
$P \propto \frac{1}{V}$ or $P V = k$ at constant $T$. This is Boyle's Law.
If we solve for $k$, ${P}_{1} {V}_{1} = {P}_{2} {V}_{2}$
Or, ${P}_{2} = \frac{{P}_{1} {V}_{1}}{V} _ 2$ $=$ $\frac{155 \cdot k P a \times 22.0 \cdot L}{10 \cdot L}$