# Can someone explain to me how to do this? Consider the following equation: 2ZnS + 3O₂ ---> 2ZnO + 2SO₂ , ΔH° = - 878.2kJ. How much heat is released when 3.0 mol ZnS reacts in excess oxygen?

Jul 1, 2014

The reaction of 3.0 mol of ZnS releases 1300 kJ.

We can write the equation as

2ZnS + 3O₂ → 2ZnO + 2SO₂ + 878.2 kJ

Then we can use a conversion factor as follows.

3.0 mol ZnS × $\left(878.2 \text{kJ")/(2"mol ZnS}\right)$ = 1300 kJ

Note: The answer can have only 2 significant figures, because that is all you gave for the moles of ZnS. If you need more precision, you will have to recalculate.

Hope this helps.