Give delta H for the combustion of propane: C3H8+5O2+3CO2+4H20 +530KCAL

Question

delta h= -530 KCAL But how do i figure out how to get this answer? Thanks!

Answer 1

C3H8 + 5O2 ==> 3CO2 + 4H2O
dHrxn = (n*dHf products) - (n*dHf reactants)
Look up the delta Hf in tables, usually in your text, multiply by moles in the balanced equation and follow the step above. Most tables I've seen give dHf in joules so you will need to convert at the end but your tables may be in cal or kcal.