At 25C and 1.0 atm, 0.25 g of a gas dissolves in 1.00 L of water. What mass of the gas dissolves in 1.00 L of water at 25C and 3.0 atm?

A 500.0 g-sample of aqueous hydrogen peroxide (H2O2) contains 31.50% H2O2 by mass.

a. Find the mass of hydrogen peroxide in the solution
b. Find the mass of water in the solution