Quiz Prep 1: Winter 2014

[Jason118]

Q3 in the first quiz prep of the workbook.
I balanced the equation and then calculated the kJ needed to break all the bonds and form all the bonds. My calculations arent matching up with the answers in the key. I'm not sure if my use of the coefficients are wrong or what not. Anyone know how to properly do it?
Thanks

[004662171]

So without seeing your work I can't tell you what you're doing wrong, but I hope this will help.

The problem asks for the reaction enthalpy for burning 1 mol of butane. To keep this 1 mol constant, we must balance the equation while maintaining a coefficient of 1 in front of butane. The reaction is balanced as so:

C₄H₁₀ + 13/2 O₂ -> 4 CO₂ + 5 H₂O

From here, you use the formula for determining reaction enthalpy using bond enthalpies, which were given in the problem.