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### bond enthalpy equations

Posted: Sat Feb 02, 2019 5:25 pm
What are the steps to help solve bond enthalpy equations? I'm having a hard time understanding.

### Re: bond enthalpy equations

Posted: Sat Feb 02, 2019 5:39 pm
If by solving bond enthalpy equations you mean using bond enthalpies to find the enthalpy of a reaction then you want to first find out which bonds are being broken and which are being formed. Then you sum the enthalpies of the breaking bonds and the forming bonds separately. Then you subtract the sum of the formed bonds from the broken bonds.

### Re: bond enthalpy equations

Posted: Sat Feb 02, 2019 5:46 pm
Bond enthalpy is defined as the amount of energy required to break a bond. You can calculate bond enthalpy of a reaction by subtracting the total bond enthalpies of products from the total bond enthalpies of reactants.

### Re: bond enthalpy equations

Posted: Sat Feb 02, 2019 7:22 pm
When solving for the enthalpy of a reaction, how do you know which bonds are supposed to be broken?

### Re: bond enthalpy equations

Posted: Sat Feb 02, 2019 7:34 pm
I believe Dr.Lavelle drew out the structure of each reactant and product in order to help us visualize which bonds were being broken.

### Re: bond enthalpy equations

Posted: Sat Feb 02, 2019 7:53 pm
In order to see which bonds are being broken, you can draw out the structures and see which ones would need to break in order to form the new structure. However, I think you can also just subtract the energy needed to break all the bonds from the energy released from forming all the bonds, which might be easier.

### Re: bond enthalpy equations

Posted: Sat Feb 02, 2019 7:53 pm
Yes drawing out the structures really worked for me