A cylinder, with a piston pressing down with a constant pressure, is filled with 2.00 moles of a gas (n1), and its volume is 50.0 L (V1). If 0.400 mole of gas leak out, and the pressure and temperature remain the same, what is the final volume of the gas inside the cylinder?

40.0 L.

Explanation:

We can use the general law of ideal gas: PV = nRT.

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

If P and T are constant, and have different values of n and V:

(V₁n₂) = (V₂n₁).

V₁ = 50.0 L, n₁ = 2.0 moles,

V₂ = ? L, n₂ = 2.0 mol - 0.4 mol = 1.6 mol.

∴ V₂ = (V₁n₂) / (n₁) = (50.0 L) (1.6 mol) / (2.0 mol) = 40.0 L.