accuracy of bond enthalpies

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Ryan Yoon 1L
Posts: 55
Joined: Mon Jul 01, 2019 12:15 am

accuracy of bond enthalpies

Postby Ryan Yoon 1L » Fri Jan 31, 2020 10:25 am

Why is it that using bond enthalpies is the least accurate method to calculate energy transfer?

Connie Chen 1E
Posts: 51
Joined: Mon Jun 17, 2019 7:24 am

Re: accuracy of bond enthalpies

Postby Connie Chen 1E » Fri Jan 31, 2020 10:31 am

Only the bond enthalpies of diatomic molecules are accurate. All other bond enthalpies are calculated from averages of many different molecules, which results in less accurate calculations.

Amanda Mei 1B
Posts: 109
Joined: Sat Aug 24, 2019 12:16 am

Re: accuracy of bond enthalpies

Postby Amanda Mei 1B » Fri Jan 31, 2020 10:35 am

For all molecules that are not diatomic, their bond enthalpies are averages from the bonds in many different molecules. For example many molecules can have a C-H bond, and the bond enthalpies of each one is different.

EvanWang
Posts: 101
Joined: Sat Sep 07, 2019 12:16 am

Re: accuracy of bond enthalpies

Postby EvanWang » Fri Jan 31, 2020 10:35 am

Because they are not tailor-made to every type of bond in every molecule, they are an average of the energy required to break bonds across many different molecules. For example, the O-H bond in CCl3COOH is different than the O-H bond in CCH3COOH because we know that the Cl pulls electrons more than H and results in a weaker O-H bond. However, we use only one value for O-H bonds when referring to bond enthalpy. Examples such as this result in inaccuracies.

Jocelyn Thorp 1A
Posts: 103
Joined: Wed Sep 18, 2019 12:20 am

Re: accuracy of bond enthalpies

Postby Jocelyn Thorp 1A » Sat Feb 01, 2020 10:44 pm

the values are experimental and are an estimate based off of a ton of different possible bond pairings!

Rosa Munoz 2E
Posts: 105
Joined: Wed Sep 18, 2019 12:21 am

Re: accuracy of bond enthalpies

Postby Rosa Munoz 2E » Sat Feb 01, 2020 10:45 pm

Because it uses averages.

Noe BM 1J
Posts: 50
Joined: Sat Sep 07, 2019 12:17 am

Re: accuracy of bond enthalpies

Postby Noe BM 1J » Sun Feb 02, 2020 6:44 pm

Because it uses the average of many molecules.

Owen-Koetters-4I
Posts: 50
Joined: Fri Sep 28, 2018 12:16 am

Re: accuracy of bond enthalpies

Postby Owen-Koetters-4I » Sun Feb 02, 2020 6:51 pm

averages are used for molecules that are not diatomic

ABombino_2J
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am

Re: accuracy of bond enthalpies

Postby ABombino_2J » Sun Feb 02, 2020 10:04 pm

The bond enthalpy method is the least accurate because all the bond enthalpy es are averages of many molecules.


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