How much heat is absorbed in the complete reaction of 3.00 grams of SiO2 with excess carbon in the reaction SiO2(g) + 3C(s) → SiC(s) + 2CO(g) ΔH° = 624.7 kJ/mol?

31.24 kJ

Explanation:

First we convert 3.00 grams of SiO₂ to moles, using its molar mass:

Now we calculate the heat absorbed, using the given ΔH°:

If the complete reaction of 1 mol of SiO₂ absorbs 624.7 kJ, then with 0.05 mol: