Question

Nitrogen gas reacts with oxygen gas to produce dinitrogen monoxide gas.
2 N2(g) + O2(g) + 163.2 kJ → 2 N2O(g)
Is this reaction endothermic or exothermic?
How do you know?

Answer 1

It is endothermic. How do you know?
2 N2(g) + O2(g) + 163.2 kJ → 2 N2O(g)
The equation tells you that 2 mols N2 will react with 1 mol of O2 and when you ADD 163.2 kJ, it gives you the products. So if you must ADD heat it is endotheric. If the 163.2 kJ was on the other side, like this, it would be exothermic. 2 N2(g) + O2(g) → 2 N2O(g) + 163.2 kJ BECAUSE that reaction tell you that 1 mols N2 react with 1 mol O2 to produce 2 mols N2O AND gives off 163.2 kJ heat.