## Methods of Enthalpy

Michael Lee 2I
Posts: 51
Joined: Fri Sep 29, 2017 7:05 am

### Methods of Enthalpy

Are we going to have to use more than one method of finding the enthalpy in any problem?

Swetha Sundaram 1E
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Been upvoted: 1 time

### Re: Methods of Enthalpy

I think we have to use different methods depending on what we're given in the problem.

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

### Re: Methods of Enthalpy

I think that he will give you a problem and based on the information he gives you, you will have to use a certain method to find the enthalpy. So I would make sure to know the various methods to calculate the enthalpy.

Dylan Mai 1D
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Joined: Sat Jul 22, 2017 3:00 am

### Re: Methods of Enthalpy

There are 3 methods we know of right now correct?

Varsha Sivaganesh 1A
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Joined: Thu Jul 13, 2017 3:00 am

### Re: Methods of Enthalpy

Dylan Mai 1D wrote:There are 3 methods we know of right now correct?

Yes! The first method is using Hess's method, the second is using bond enthalpies, and the third is using standard enthalpies of formation. So it just depends on what information the question gives you.

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

### Re: Methods of Enthalpy

Hess's Law (method 1) is a state function, which means it must be additive. The enthalpy change at each step of a multi-step reaction can be added to give the total enthalpy change. Bond enthalpies (method 2) are always positive and endothermic. The reactants (bonds broken) require energy, and the products (bonds formed) release energy.

Naana Boateng 1I
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Joined: Fri Sep 29, 2017 7:07 am

### Re: Methods of Enthalpy

Possibly, it depends on the type of question that Lavelle puts on his test, and whether or not there will be an A, B or C. Just be prepared for anything at this point.

aaron tang 2K
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Joined: Thu Jul 27, 2017 3:01 am

### Re: Methods of Enthalpy

It honestly depends on the question because there are 3 methods of enthalpy. 1. Hess' Method 2. Bond Enthalpies 3. Standard Enthalpies of Formation

AnuPanneerselvam1H
Posts: 52
Joined: Fri Sep 29, 2017 7:07 am

### Re: Methods of Enthalpy

Yes we learned three methods. The first one involves Hess's Law, the second one uses bond enthalpies, and the third one uses standard enthalpies of formation. The method you use depends on the information given.