Two moles of an ideal gas are compressed isothermally and reversibly from 40 L to 20 L at 300 K . What is the work done? $\left(\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right)$

Calculate the enthalpy change when 12 g carbon react with sufficient hydrogen to form methane. If enthalpy of formation of methane is $-75 \mathrm{~kJ} \mathrm{~mol}^{-1}$.

Which among the following pair of properties are intensive?

2 moles of an ideal gas expands isothermally from $5 \mathrm{dm}^3$ to $10 \mathrm{dm}^3$ at a constant external pressure of 1.5 bar. Calculate work done.