(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

http://imgur.com/lb0HL

2. Relevant equations

in pic

3. The attempt at a solution

So I multiplied the H2 + 1/2O2 equation by 3 and added it to the (N2H4, 2NH3) equation.

I got H2O to match up and O2 to match up, but I don't know how to manipulate the other

equations to get 4N2 to match up. Do I divide all by four? I don't know.

Please help.

Thanks

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# Homework Help: Standard change of enthalpy, hess's law question

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