Hess Law

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Michael Lee 2I
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Joined: Fri Sep 29, 2017 7:05 am

Hess Law

Postby Michael Lee 2I » Fri Jan 12, 2018 5:51 pm

Can someone explain Hess’ law and how it pertains to the net reaction? I followed during class but was a bit confused about this.

Ammar Amjad 1L
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Joined: Thu Jul 27, 2017 3:00 am
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Re: Hess Law

Postby Ammar Amjad 1L » Fri Jan 12, 2018 6:30 pm

Hess's law states that energy changes are state functions. The enthalpy change at each step of a multi-step step reaction can be added to give the total enthalpy change.

ConnorThomas2E
Posts: 57
Joined: Fri Sep 29, 2017 7:04 am

Re: Hess Law

Postby ConnorThomas2E » Fri Jan 12, 2018 9:52 pm

Hess' law states that a specific reaction is equal to the sum of the enthalpies of any set of reactions equal to the specific reaction. This means that if you have the enthalpies for reactions that can be added together to make another reaction, you can add the enthalpies together to find the net enthalpy of the new reaction.

Jasmin Tran 1J
Posts: 54
Joined: Thu Jul 27, 2017 3:00 am

Re: Hess Law

Postby Jasmin Tran 1J » Sat Jan 13, 2018 1:42 am

For more clarification, Hess's Law essentially states that the energy of a chemical reaction is the same regardless of the number of steps needed/reaction mechanism.

Tanaisha Italia 1B
Posts: 55
Joined: Fri Sep 29, 2017 7:04 am

Re: Hess Law

Postby Tanaisha Italia 1B » Sat Jan 13, 2018 3:30 am

Hess's Law states that enthalpy is a state function, so the total change in enthalpy after a specific reaction will be the same regardless of the number of steps taken to achieve that reaction or how much work was involved. If you add together the change in enthalpy at each step, you will get the total change in enthalpy. It was likened to altitude in class. No matter how much work it took to get to that height, the height itself is the same.


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