Question

Calculate the change in internal energy of 3.00 mol of helium gas when its temperature is
increased by 2.00 K.

Answer 1

Internal energy

$U=\frac{3}{2}nRT$

$∆U=\frac{3}{2}nR∆T$

Put value

$∆U=\frac{3}{2}\times3\times8.31\times2=74.79J$