I am also going to need help with the discussion and conclusion, i found this experiment hard, so I don't really know what to write... please dont be to harsh:
Discussion and Conclusions: In this experiment we applied Hess’s Law. To the following reactions. H2¬¬¬(g) + ½ O2 (g) H2O using the formula, ΔHfº(H2O)=-285.84kj/mole. For solution: Mg(s)+2H(aq)Mg(aq)H2(g) applying formula ΔHb=-516.6kj/mole. Solution: Mg¬¬2+(aq)+H2O(l)MgO(s) + 2H(aq) ΔHc=145.8kj/mole. By adding the equations Mg(s)+1/2 O2(g)MgO(s)= -656.64.The accepted value of ΔHf for the formation of MgO is -601.75kj/mole. Our percent deviation of our value is 2% error which leads us to think that we were very close and precise.