# A gas occupies 1.58 liters its pressure is 5.2 atm and its temperature is 57.4°C. What would volume be if the pressure were decreased to 3.59 atm?

At constant $T$, pressure is inversely proportional to volume: this is Boyle's law.
Given $P \propto \frac{1}{V}$, ${P}_{1} {V}_{1} = {P}_{2} {V}_{2}$, and the great advantage of this proportionality is that we can use unorthodox units of pressure and volume, i.e. $\text{psi, pints, atmosphere, gallons}$ so long as we are consistent.
We want ${V}_{2}$ $=$ $\frac{{P}_{1} {V}_{1}}{P} _ 2$ $=$ $\frac{5.2 \cdot \cancel{a t m} \times 1.58 \cdot L}{3.59 \cdot \cancel{a t m}}$ $\cong$ 2*L?