Answer to Question #306397 in Molecular Physics | Thermodynamics for Vill

Question

A mass m of helium gas is in a container of constant volume V. It is initially at pressure P and absolute (Kelvin) temperature T. Additional Helium is added, bringing the total mass of helium gas to 3m. After this addition, the temperature is found to be 2T. What is the final gas pressure?

Answer 1

Solution;

From Ideal gas equation;

$PV=mRT$

Volume is constant;

$P_fV=3mR2T=6mRT$

Comparing both equations;

$P=\frac{P_f}{6}$

Hence;

$P_f=6P$