Propane (C3H8) burns according to the following balanced equation: C3H8(g)+5O2(g)→3CO2(g)+4H2O(g) Part A Calculate ΔH∘rxn for this reaction using standard enthalpies of formation. (The standard enthalpy of formation of gaseous propane is -103.9 kJ/mol .) Express the enthalpy in kilojoules to four significant figures.

Answer 1

C3H8(g)+5O2(g)→3CO2(g)+4H2O(g)
dHrxn = (n*dHo formation proeducts) - (n*dHo formation reactants)
You are given the dH for C3H8. You will need to look up dHo formation for H2O (g) and CO2(g) and plug them into the equation above. Post your work if you get stuck.
By the way, I have answered a number of your questions over the last day or so and you have shown no thinking on any of them. This site is not a homework dump site. We want to HELP you learn how to do this by yourself. We don't want to do all the work. Henceforth, please explain how you think the problem might be worked or at least tell us what you don't understand about the problem; i.e., what part is giving you trouble and why.