A gas absorbs $$200 \mathrm{~J}$$ heat and expands by $$500 \mathrm{~cm}^3$$ against a constant external pressure $$2 \times 10^5 \mathrm{~N} \mathrm{~m}^{-2}$$. What is the change in internal energy?

Which among the following pair of properties is intensive?

If $$8.84 \mathrm{~kJ}$$ heat is liberated for formation of $$3 \mathrm{~g}$$ ethane, calculate its $$\triangle_{\mathrm{f}} \mathrm{H}^{\circ}$$.

The difference between $$\Delta \mathrm{H}$$ and $$\Delta \mathrm{U}$$ is usually significant for systems consisting of :