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Week 10 Discussion Notes (2E,2I,2K)

Posted: Fri Mar 15, 2019 3:04 pm
by Chem_Mod
Dear all,

Attached please find the worksheet answer key and discussion notes.

Good luck on your finals! ٩(๑>◡<๑)۶

Best,
Joyce

Re: Week 10 Discussion Notes (2E,2I,2K)

Posted: Sat Mar 16, 2019 1:17 pm
by Meachelle_Lum_1I
Hi, does anyone know why delta H was 300 and not -300 when calculating the reverse activation energy? Didn't they give it as -300, and it's an exothermic reaction so deltaH should be negative?

Re: Week 10 Discussion Notes (2E,2I,2K)

Posted: Sat Mar 16, 2019 1:47 pm
by Tony Ong 3K
Thank you so much this quarter Joyce!!!
Definitely the greatest TA to have walked this Earth.

Re: Week 10 Discussion Notes (2E,2I,2K)

Posted: Sat Mar 16, 2019 2:49 pm
by Chem_Mod
Meachelle_Lum_1I wrote:Hi, does anyone know why delta H was 300 and not -300 when calculating the reverse activation energy? Didn't they give it as -300, and it's an exothermic reaction so deltaH should be negative?


For the reverse reaction, new delta H = - delta H. The forward reaction is exothermic and delta H = -300, then the reverse reaction is endothermic and delta H = +300.

Hope this helps.

Re: Week 10 Discussion Notes (2E,2I,2K)

Posted: Sat Mar 16, 2019 3:53 pm
by Samantha Silva 1F
Thank you for the worksheet!

Re: Week 10 Discussion Notes (2E,2I,2K)

Posted: Sat Mar 16, 2019 7:59 pm
by Kobe_Wright
Thank You!

Re: Week 10 Discussion Notes (2E,2I,2K)

Posted: Sat Mar 16, 2019 8:30 pm
by Kobe_Wright
Meachelle_Lum_1I wrote:Hi, does anyone know why delta H was 300 and not -300 when calculating the reverse activation energy? Didn't they give it as -300, and it's an exothermic reaction so deltaH should be negative?

Going in reverse, you'd switch the sign around. You're doing the reaction backwards.