Question

Carbon monoxide reacts with oxygen to form
carbon dioxide by the following reaction:
2CO(g) + O2(g) --> 2CO2(g)

change in H for this reaction is −135.28 kcal.
If 811.7 kcal is released, how many moles of
CO must have reacted?
1. 16.3 mol
2. 40.5 mol
3. 12.0 mol
4. 5.41 mol
5. 6.00 mol
6. 1.35 mol
7. 270.5 mol

Answer 1

Didn't I do the Al2O3 for you? That should show you how to do it.
Basically, reword the question. 135 kcal are released when 2 mols CO are consumed. How may mols CO must be consumed to produce 811.7 kcal. That's
2 x (811.7/135.28) = ?