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Determining Rate Constant (Exercise 15.63, Sixth Edition)

Posted: Fri Mar 15, 2019 9:48 pm
by KatelinTanjuaquio 1L
Question 15.63 of the sixth edition asks, "The rate constant of the reaction between CO2 and OH- in aqueous solution to give the HCO3- ion is 1.5*10^10 L*mol-1 at 25 degrees celsius. Determine the rate constant at blood temperature 37 degrees celsius, given that the activation energy for the reaction is 38 kJ*mol-1. " The solution manual gives the solution as shown in the screenshot.

Screen Shot 2019-03-15 at 9.33.17 PM.png


However, when I perform the calculations, I get a different answer. For example, I get 0.059 instead 0.59, resulting in a completely different overall answer. When I plug in 0.59 in however, I get the same answer as the solution manual. The only thing I think might be off is the gas constant, but that should be given. Can anybody provide insight?

Re: Determining Rate Constant (Exercise 15.63, Sixth Edition)

Posted: Fri Mar 15, 2019 9:52 pm
by Kassidy Tran 1E
I’m stuck on the same problem, where does it -0.59 come from?

Re: Determining Rate Constant (Exercise 15.63, Sixth Edition)

Posted: Fri Mar 15, 2019 9:56 pm
by KatelinTanjuaquio 1L
I think it's supposed to be an equal sign, maybe? The equation for that doesn't involve subtraction.

Re: Determining Rate Constant (Exercise 15.63, Sixth Edition)

Posted: Fri Mar 15, 2019 10:03 pm
by Kassidy Tran 1E
KatelinTanjuaquio 1L wrote:I think it's supposed to be an equal sign, maybe? The equation for that doesn't involve subtraction.

Okay thank you this makes a lot more sense now. When I enter the values into my calculator I get the same values as the solutions manual. Are you inputting the gas constant as 8.314x10^-3 kJ/(mol*K)? That might be throwing your calculations off if you arent plugging in the gas constant in terms of kJ.

Re: Determining Rate Constant (Exercise 15.63, Sixth Edition)

Posted: Fri Mar 15, 2019 10:04 pm
by keyaluo4C
The reason you get 0.059 is because for some reason the solutions does not convert kj to j. If you convert kj to j in the beginning, you should get 0.59.

Re: Determining Rate Constant (Exercise 15.63, Sixth Edition)

Posted: Fri Mar 15, 2019 10:09 pm
by KatelinTanjuaquio 1L
When I input the value of 8.314x10^-3, I get the same answer as the solution manual. However, the solution manual uses 8.314x10^-2 for some reason, and I don't know why. When I plug that value into my work, I get different answers for the whole thing.