According to Henry's law C = k P
where C = concentration of gas (g/L)
k : Henry's constant
P : pressure of gas above the solution
concentration of gas = 5.6 g / 3.5 L = 1.6 g/L
From Henry's law:
C₁ / C₂ = P₁ / P₂
C₂ = C₁P₂ / P₁ = (1.6 * 5 atm) / 2.5 atm = 3.2 g/L
so the 3.5 L will contain 11.2 g gas
