Answer:
Mercury and oxygen react to yield mercuric oxide. > 2Hg + O2 = 2HgO
Calcium and water react to yield calcium hydroxide and hydrogen. > Ca + 2H2O = Ca(OH)2 + H2
Hydrogen and chlorine react to yield hydrochloric acid. > H2 + Cl2 = 2HCl
Iron and sulfer react to yield iron sulfide. > Fe + S = FeS
Step-by-step explanation: