Rate constant

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Meachelle_Lum_1I
Posts: 92
Joined: Fri Sep 28, 2018 12:24 am

Rate constant

Postby Meachelle_Lum_1I » Mon Mar 11, 2019 3:16 pm

Can rate constants be negative?

Rogelio Bazan 1D
Posts: 64
Joined: Tue Nov 14, 2017 3:01 am

Re: Rate constant

Postby Rogelio Bazan 1D » Mon Mar 11, 2019 3:25 pm

In Kinetics and for the scope of this class, the rate constant will never be negative. The Arrhenius equation is always positive (otherwise, the rate constant would be Zero). If the rate constant was zero then this would indicate that the reaction is not occurring at all. Please, someone, correct me if I am wrong otherwise hope this helps.

JT Wechsler 2B
Posts: 62
Joined: Fri Sep 28, 2018 12:16 am

Re: Rate constant

Postby JT Wechsler 2B » Mon Mar 11, 2019 3:32 pm

No, the rate constant will not be negative.

Vanadium Wang 4H
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

Re: Rate constant

Postby Vanadium Wang 4H » Tue Mar 12, 2019 9:43 pm

Rate constant k should always be positive.

From the Arrhenius Equation, we know k = A x exp(-Ea/RT).
"A" (frequency factor) will always be positive because (according to Google) there are no experimental cases where A is negative, and mathematically exp(-Ea/RT) can never be negative.

If rxn is 2nd order, line plot has a slope of +k.
If rxn is 1st or 0 order, line plot has a slope of -k.

Yiting_Gong_4L
Posts: 69
Joined: Fri Sep 28, 2018 12:25 am

Re: Rate constant

Postby Yiting_Gong_4L » Tue Mar 12, 2019 11:19 pm

the rate constant, k, will always be positive!


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