Beings which claimed to show . H 2 3Fe (s) + 30 2 2Cr 2 0 -> Fe 3 0 4 aspirin, C g H 9 N 4 0 2 (g) -> 2MgO (s), AH = lllkj mol' 1 . Write a thermochemical equation which expresses this. 2C(s) (graphite) + 2H 2 (g) + 70 2 (g) .