Given the reactions (1) and (2) below, determine (i) ΔrH° and ΔrU° for reaction (3), (ii) ΔfH° for both HI(g) and H2O(g), all at 298 K.
(1) H2(g) + I2(s) → 2 HI(g) ΔrH° = +52.96 kJ mol-1
(2) 2 H2(g) + O2(g) → 2 H2O(g) ΔrH° = -483.64 kJ mol-1
(3) 4 HI(g) + O2(g) → 2 I2(s) + 2 H2O(g)