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 :

What is change in internal energy when system releases $$8 \mathrm{~kJ}$$ of heat and performs $$660 \mathrm{~J}$$ of work on the surrounding?