Hi, I’ve been having issues to understand this question about energy change, so here it goes.
Calculate the energy change in the following reaction:
a) burning 1 mole of ethanol - C2H5OH + 3O2 —> 2CO2 + 3 H2O
So first you need to calculate the energy required to break the bonds between the reactant atoms:
1 C-C bond = 348
5 C-H bonds = (5 x 413) = 2065
1 O-H bond = 463
1 C-O bond = 360
3 O=O bonds = (3 x 498) = 1494
Total = 4730 kJ
Then we need to do the same for the bonds that are being made (in the products). But here’s my problem, my text book says those are the bonds in the products:
4 C=O bonds = (4 x 743) = 2972
6 O-H bonds = (6 x 463) = 2778
Total = 5750 kJ
However, looking at the equation above I see 2CO2, wouldn’t that give us, along with the 4 C=O bonds, 1 C-C bond? Even though carbon makes only 4 bounds, I don’t know if it makes sense for them to be separated. Or are the two molecules separated?
Thank you for your attention, and please help me!!