Determine by calculation and diagrames to proof whether these two reactions are endothermic or exothermic ..

Question

1. Methane burns in oxygen

2. Nitrogen (II) reacting with oxygen producing nitrogen monoxide.

Answer 1

I'll do the first one; you do the second.
CH4 + 2O2 --> CO2 + 2H2O
dHrxn = (n*dHf products) - (n*dHf reactants)
If dHrxn is -, rxn is exothermic.
If dHrxn is +, rxn is endothermic.