Question

The percent is confusing me, can you please help me set this equation up.
How much heat is liberated when 5.00 kg of coal is burned if the coal is 96.2% carbon by mass and the other materials in the coal do not react?
(delta)H comb of carbon is -394kJ/mol
thank you

Answer 1

If that is all that's confusing you the easiest way to take care of it is that you don't start with 5.00 kg but 5.00 kg x 0.962 = ? kg and I would change that to grams.
mols C = grams/atomic mass C = ?

Then 395 kJ/mol x # mols = ? kJ released. Personally I don't believe in making that a negative sign IF YOU SAY RELEASED since released means it is exothermic. Placing a negative sign means it is saying released released and that doesn't make sense to me.

Answer 2

so would I just do 5.00*.962, then make that into grams, them do 394*C? or where do I find the moles?

Answer 3

I don't think you read my response.
Re-read. mols C = grams/atomic mass C.