For each of the subsequent gas-phase reactions state the rate expression in terms of the appearance of each product or disappearance of each reactant.
2H2O(g) -> 2H2(g) +O2(g)
rate = ?[H2O]/?t
rate = ?[H2]/?t
rate = ?[O2]/?t
Then for,
2SO2(g) + O2(g) ->2SO3(g)
and
2NO(g) + 2H2(g) -> N2(g) +2H2O(g).