The pressure exerted on a 240. ml sample of hydrogen gas at constant temperature is increased from 0.428 atm to 0.724 atm. what will the final volume of the sample be?

Based on the fact that the question mentions a change in pressure and the aim is to determine the change in volume, then it is evident that the premise of the question is Boyle's law (Pressure increase when Volume decrease and vice versa when the temperature remains constant). Thus Boyle's Equation can be used to determine the answer.

Boyle's Equation:      P₁V₁    =    P₂V₂

Since the initial pressure (P₁) is 0.428 atm, the final pressure (P₂) is 0.724 atm, the initial volume is 240 mL, then we can substitute these into the equation to find the final volume (V₂).

                                                     P₁V₁    =    P₂V₂
∴ by substituting the known values,
                 ⇒       (0.428 atm) (240 mL)  =  (0.724 atm) (V₂)

                 ⇒         V₂    =    

                 ⇒         V₂    =  141.88 mL

Thus the final volume of the sample is approx. 141.88 mL