The $\Delta$H value for the reaction is -90.8 kJ.How much heat is released when 66.9 g Hg is reacted with oxygen?

Question

The $\Delta$H value for the reaction  is -90.8 kJ.How much heat is released when 66.9 g Hg is reacted with oxygen?

Quizplus · Accepted Answer

First we need to balance the chemical equation for the reaction of mercury with oxygen:
2Hg + O2 → 2HgO
Next, we need to calculate the amount of moles of Hg involved in the reaction:
66.9 g Hg / 200.59 g/mol = 0.333 mol Hg
Using the value of ∆H from the given reaction and the amount of moles of Hg being reacted, we can calculate the amount of heat released:
∆H = -90.8 kJ/mol
q = ∆H x n
q = (-90.8 kJ/mol) x (0.333 mol Hg) = -30.3 kJ
The negative sign indicates that heat is being released by the reaction. Therefore, the answer is (C) 30.3 kJ.

The Δ\DeltaΔ H Value for the Reaction Is -90 ×\times× 103 KJ C)30

The $\Delta$ H Value for the Reaction Is -90 $\times$ 10³ KJ
C)30