Question

A vessel of volume $8.0\times {10}^{-3}{m}^3$ contains an ideal gas at 300k and 200k Pa. The gas is allowed to leak till the pressure falls to 125 k Pa. Calculate the amount of gas (in moles) leaked assuming that the temperature remains constant.

• A. 0.24 moles
• B. 0.34 moles
• C. 0.44 moles
• D. 0.54 moles

Answer 1

The correct option is A 0.24 moles

Temperature and volume are constants.
$n=\frac{PV}{RT}or{n}_i=\frac{P_{i}V}{RT}and{n}_f=\frac{P_{f}V}{RT}$
Amount leaked $=n_i-n_f=\frac{(P_i-P_f)V}{RT}$
$=\frac{(200-125)\times {10}^3\times (8.0\times {10}^{-3})}{8.31\times 300}=0.24moles$