Complete the balanced chemical equation, including physical states, that describes the decomposition of magnesium hydroxide when it is heated.
[ Select ] ["3", "2", "1"] Mg(OH)2 [ Select ] ["(g)", "(aq)", "(l)", "(s)"] ⟶ [ Select ] ["2", "1", "3"] MgO [ Select ] ["(s)", "(g)", "(aq)", "(l)"] + [ Select ] ["1", "2", "3"] H2O [ Select ] ["(s)", "(l)", "(g)", "(aq)"]