Calculating Average Kinetic Energy

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Tiffany Chao 2H
Posts: 117
Joined: Fri Aug 09, 2019 12:17 am

Calculating Average Kinetic Energy

Postby Tiffany Chao 2H » Sat Feb 08, 2020 5:56 pm

For 4.19, we're supposed to use average kinetic energy = 3/2*RT. I did 3/2(8.314 J/mol.K)(328.85K) and got 4101.09 J/moles. However, the answer key says 4103.2 J/mol. I'm off by a pretty significant amount and I'm not sure what I'm doing wrong since it seems to be a pretty straightforward calculation.


Jared Khoo 1G
Posts: 107
Joined: Wed Sep 18, 2019 12:16 am

Re: Calculating Average Kinetic Energy

Postby Jared Khoo 1G » Sun Feb 09, 2020 4:56 pm

When converting celcius to kelvin, you added 273. For a more accurate conversion, add 273.15 as mentioned on Dr. Lavelle's formula sheet. Also, the textbook probably used R = 8.3145 as the gas constant. This should get the right answer.

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