# The pressure exerted on 800mL of a gas is decreased from 300 kPa to 198 kPa. What is the new volume of the gas if the temp remains constant?

${V}_{2} = 1200 \cdot m L \ldots \ldots . .$
At constant temperature, $P V = k$, for a fixed amount (mass) of gas. This is old Boyle's Law:
Since $P V = k$, ${P}_{1} {V}_{1} = {P}_{2} {V}_{2}$
V_2=(P_1V_1)/P_2=(300*kPaxx800*mL)/(198*kPa)=??*mL. A good question in that you don't have to use a calculator.........