Bond Enthalpies

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Clara Cho 2K
Posts: 103
Joined: Wed Sep 18, 2019 12:18 am

Bond Enthalpies

Postby Clara Cho 2K » Thu Jan 30, 2020 1:34 pm

Why is using bond enthalpies the least accurate method to calculate enthalpy changes?

Kate Osborne 1H
Posts: 102
Joined: Fri Aug 30, 2019 12:16 am

Re: Bond Enthalpies

Postby Kate Osborne 1H » Thu Jan 30, 2020 1:36 pm

bond enthalpies is the least accurate because bond enthalpy is an average value not a standard value

Abhi Vempati 2H
Posts: 104
Joined: Fri Aug 09, 2019 12:17 am

Re: Bond Enthalpies

Postby Abhi Vempati 2H » Thu Jan 30, 2020 8:59 pm

A measured bond enthalpy is the average value of a bond that was calculated from many different molecules, so it is less accurate.

A C–H bond demonstrates this perfectly. When we look at CH4, C2H2, and CHCl3, the bond enthalpy for each C–H bond will be different for each molecule. So, in order to get the value listed in the table, the average bond enthalpy has to be calculated from many different molecules with C–H bonds. This causes a noticeable amount of inaccuracy when compared to other methods.

Betania Hernandez 2E
Posts: 107
Joined: Fri Aug 02, 2019 12:15 am

Re: Bond Enthalpies

Postby Betania Hernandez 2E » Fri Jan 31, 2020 12:26 am

Bond enthalpies are the least accurate method to calculate enthalpy changes because they are an average of many bonds.

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

Re: Bond Enthalpies

Postby Amanda Mei 1B » Fri Jan 31, 2020 10:42 am

Aside from the fact that bond enthalpies of non-diatomic molecules are averages from the bonds of many different molecules, their values may vary depending on which chart you use. Since there's no universally agreed upon standard for which molecules are used to determine a bond, those making the chart decide.

Zoe Gleason 4F
Posts: 51
Joined: Tue Jul 23, 2019 12:15 am

Re: Bond Enthalpies

Postby Zoe Gleason 4F » Fri Jan 31, 2020 10:55 am

Bond enthalpies are average, whereas in other methods they are more specific.

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