# The pressure on a sample of an ideal gas is increased from 715 mmHg to 3.55 atm at constant temperature. If the initial volume of the gas is 485 mL, what is the final volume of the gas?

The gas is compressed to a volume of $129 \cdot m L$.
At constant $T$, ${P}_{1} {V}_{1} = {P}_{2} {V}_{2}$; this is Boyle's law.
Now ${P}_{1} = \frac{715 \cdot m m \cdot H g}{760 \cdot m m \cdot H g \cdot a t {m}^{-} 1} = 0.941 \cdot a t m$
${V}_{2} = \frac{{P}_{1} {V}_{1}}{P} _ 2 = \frac{0.941 \cdot \cancel{a t m} \times 485 \cdot m L}{3.55 \cdot \cancel{a t m}} = 129 \cdot m L$