Question

A 200g of gas was heated from 50°C to around 120°C. The gas expanded in a piston-cylinder apparatus from 2.0L of initial volume to find a volume of 10.0L against an external pressure of 3.0 atm. Calculate for the change in the internal energy. The specific heat of water is 2.19 J/g×°C)

Answer 1

Solution;

$\Delta u=q+W$

$q=mC\Delta T$

$q=200×2.19(120-50)$

$q=30660J$

$W=-P(V_2-V_1)$

$W=-303.975(10-2)$

$W=2431.8J$

Hence;

$\Delta u=30660-2431.8=28.23kJ$