Question

Given the equation 2Mg(s) + O2(g) → 2MgO(s) + 72.3 kJ, how much heat is involved in the production of 5.0 mol of MgO?

Answer 1

The reaction is not endothermic because it is not absorbing energy, it is an exothermic reaction, resulting in a negative product. ANSWER: -72.3 kJ

Answer 2

The Balance Chemical equation is as follow,

2 Mg (s) + O₂(g) → 2 MgO(s) + 72.3 kJ

According to this equation,

2 Moles of MgO formation involved = 72.3 kJ of Heat
So,
5 Moles of MgO formation will involve = X kJ of Heat

Solving for X,
X = (5 Moles × 72.3 kJ) ÷ 2 Moles

X = 180.75 kJ of Heat