Hess’ Law

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Kristina Rizo 2K
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Hess’ Law

Postby Kristina Rizo 2K » Sun Feb 02, 2020 7:24 pm

Can someone explain to me what Hess’ Law is exactly and what equations pertain to it please.

Sukanya Mohapatra 2G
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Re: Hess’ Law

Postby Sukanya Mohapatra 2G » Sun Feb 02, 2020 7:27 pm

Hess's Law states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes.

KarineKim2L
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Joined: Fri Aug 30, 2019 12:16 am

Re: Hess’ Law

Postby KarineKim2L » Sun Feb 02, 2020 7:30 pm

By stating that the pathway of a reaction does not matter for the total change in enthalpy, the Hess's law allows us to add the separate changes in enthalpies of separate reactions to get the total change in enthalpy of the sum reaction.

LeAirraBullingor2k
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Re: Hess’ Law

Postby LeAirraBullingor2k » Sun Feb 02, 2020 8:49 pm

Hess's law allows us to calculate the total enthalpy change in a reaction regardless of what steps had to be taken to get to a certain chemical equation.

ABombino_2J
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Re: Hess’ Law

Postby ABombino_2J » Sun Feb 02, 2020 9:33 pm

Hess’ Law is essentially the definition of a state function for enthalpy.

Janet Nguy 2C
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Re: Hess’ Law

Postby Janet Nguy 2C » Sun Feb 02, 2020 9:38 pm

To add on to what everyone said above, Hess's law can be useful for finding the total enthalpy for a reaction if you are given multiple sub-reactions. You then manipulate all the sub-reactions to obtain the one they ask for, and then calculate the total enthalpy by adding all the enthalpies of the sub-reactions you found.

Nathan Rothschild_2D
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Re: Hess’ Law

Postby Nathan Rothschild_2D » Sun Feb 02, 2020 9:58 pm

It's a way to find the total change in enthalpy when multiple subreactions are occurring.

saigorijavolu2k
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Re: Hess’ Law

Postby saigorijavolu2k » Sun Feb 02, 2020 10:04 pm

Hess's Law uses the enthalpies of intermediary reactions to calculate the total enthalpy. By using Hess's law , you are manipulating reactions to get rid of the intermediary reactants/products and up with the reaction you want. You then factor those manipulations into your calculations for enthalpy.

Daniel Yu 1E
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Joined: Sat Aug 24, 2019 12:15 am

Re: Hess’ Law

Postby Daniel Yu 1E » Sun Feb 02, 2020 10:10 pm

Hess's Law states that the total enthalpy is independent of the intermediate reactions. This means you can add up the enthalpy changes of intermediate reactions to find the overall enthalpy change of the reaction. You use it for enthalpy change questions.

Trent Yamamoto 2J
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Re: Hess’ Law

Postby Trent Yamamoto 2J » Sun Feb 02, 2020 10:44 pm

Hess's Law establishes that the total enthalpy change for the reaction is the sum of all changes.

Anushka Chauhan2B
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Re: Hess’ Law

Postby Anushka Chauhan2B » Sun Feb 02, 2020 10:54 pm

the total enthalpy change for the reaction is the sum of all changes


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