The volume of a sample of hydrogen gas was decreased from 11.63 L to 4.92 L at constant temperature. If the final pressure exerted by the hydrogen gas sample was 7.20 atm, what pressure did the hydrogen gas exert before its volume was decreased

3.05 atm

Explanation:

According to Boyle's law, the pressure exerted by a gas at constant temperature is inversely proportional to the volume of the gas.

Mathematically, the law can be expressed as:

P1V1 = P2V2

In this case, P1 = ?, V1 = 11.63 L, P2 = 7.20, V2 = 4.92 L

P1 = P2V2/V1              

         = 7.20 x 4.92/11.63

           = 3.05 atm

The pressure the hydrogen gas exerted before its volume decreased is 3.05 atm.