Need help with basic thermochemistry!

[Exploited]

I'm in general chemistry 1 and I have a homework assignment due tomorrow but I can find nothing to help me along with it.

The question states:

From the following heats of reaction,

2 C(graphite) + H2(g) -->C2H2(g) ΔH=227 kJ/mol

6 C(graphite) + 3 H2(g) --> C6H6(l) ΔH=49 kJ/mol


Calculate the heat for the reaction 3 C2H2(g) --> C6H6(l)



Could anyone please point me in the right direction for solving this problem? I know it is very basic but I haven't been paying attention like I should have been. I'm not asking for you to do my homework, I'd like to actually learn how to do this..


Thanks

[2bfrank]

google it

[KaBoom]

Im no expert but heres what id do:

2C + H2 --227--> C2H2

3(2C + H2) --3(49)--> C6H6

227-3(49)= 80

= 80kJ/mol

That is the principal of Hess Cycles... Google Hess's Law for more info on it. Sorry if im wrong... :)