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Rate constant

Posted: Mon Mar 11, 2019 3:16 pm
by Meachelle_Lum_1I
Can rate constants be negative?

Re: Rate constant

Posted: Mon Mar 11, 2019 3:25 pm
by Rogelio Bazan 1D
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.

Re: Rate constant

Posted: Mon Mar 11, 2019 3:32 pm
by JT Wechsler 2B
No, the rate constant will not be negative.

Re: Rate constant

Posted: Tue Mar 12, 2019 9:43 pm
by Vanadium Wang 4H
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.

Re: Rate constant

Posted: Tue Mar 12, 2019 11:19 pm
by Yiting_Gong_4L
the rate constant, k, will always be positive!