Bond enthalpy not given

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505095793
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Joined: Fri Sep 28, 2018 12:25 am

Bond enthalpy not given

Postby 505095793 » Wed Jan 30, 2019 10:24 am

If the bond enthalpy is not given how would we calculate the reaction enthalpy?

Manya Bali 4E
Posts: 66
Joined: Fri Sep 28, 2018 12:23 am

Re: Bond enthalpy not given

Postby Manya Bali 4E » Wed Jan 30, 2019 10:45 am

There are two other ways. One is that the enthalpy of the reaction equals the sum of the enthalpies of formations of the products minus the sum of the enthalpies of formation for the products. The other way is to use Hess's method and add together the enthalpies of different reactions if, together, the reactions form the reactants/products you want.

LorenzoDuvergne3I
Posts: 60
Joined: Fri Sep 28, 2018 12:25 am

Re: Bond enthalpy not given

Postby LorenzoDuvergne3I » Wed Jan 30, 2019 11:18 am

It should be noted that the other two methods also require some sort of given information, either the enthalpies of formation or the enthalpies of each reaction, so which method you use depends on what information the problem gives you.

Clarissa Cabil 1I
Posts: 66
Joined: Fri Sep 28, 2018 12:19 am

Re: Bond enthalpy not given

Postby Clarissa Cabil 1I » Wed Jan 30, 2019 12:15 pm

If a certain bond enthalpy is not given, also note if the bond is between elemental molecules at their most natural state at standard conditions (E.g. O2 (g), F2 (g)) in which the bond enthalpy is assumed to be equal to 0.

Hope this helps!


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