Given the following thermochemical equations: A(g) → B(g) ∆H° = 15 kJ 2B(g) → C(s) ∆H° = –25 kJ C(l) → C(s) ∆H° = –20 kJ C(g) → C(l) ∆H° = –30 kJ Determine the standard enthalpy change, ∆H° , for the following equation: 2A(g) → C