What is the value of $$\mathrm{\Delta H-\Delta U}$$ for the formation of 2 moles of ammonia from $$\mathrm{H_{2(g)}}$$ and $$\mathrm{N_{2(g)}}$$ ?

Two moles of an ideal gas are expanded isothermally from $$15 \mathrm{dm}^3$$ to $$20 \mathrm{dm}^3$$. If the amount of work done is $$-6 \mathrm{dm}^{-3}$$ bar, find external pressure needed to obtain this work.

Find the value of $$-197^\circ$$C temperature in Kelvin.

Which among the following is NOT an extensive property?