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Hess Law

Posted: Fri Jan 12, 2018 5:51 pm
by Michael Lee 2I
Can someone explain Hess’ law and how it pertains to the net reaction? I followed during class but was a bit confused about this.

Re: Hess Law

Posted: Fri Jan 12, 2018 6:30 pm
by Ammar Amjad 1L
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.

Re: Hess Law

Posted: Fri Jan 12, 2018 9:52 pm
by ConnorThomas2E
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.

Re: Hess Law

Posted: Sat Jan 13, 2018 1:42 am
by Jasmin Tran 1J
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.

Re: Hess Law

Posted: Sat Jan 13, 2018 3:30 am
by Tanaisha Italia 1B
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.