Rate Constant

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Jessica Helfond 2F
Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

Rate Constant

Postby Jessica Helfond 2F » Tue Mar 05, 2019 7:48 pm

Could someone explain what the rate constant (k) actually represents within a reaction?

Vincent Li 4L
Posts: 48
Joined: Fri Sep 28, 2018 12:19 am

Re: Rate Constant

Postby Vincent Li 4L » Tue Mar 05, 2019 8:04 pm

The concentrations and orders of the reactants represent the reaction mechanism (how many molecules must collide for the reaction to proceed, which is more clear when we go into elementary reactions), whereas the rate constant k depends on the temperature and activation energy. The higher the value of k, the faster the rate of the reaction, so we can make the conclusion that higher temperatures and lower activation energies correspond with larger rate constants k. Hope this helps.

JiangJC Dis2K
Posts: 72
Joined: Fri Oct 12, 2018 12:16 am

Re: Rate Constant

Postby JiangJC Dis2K » Tue Mar 05, 2019 8:05 pm

The rate constant is basically the derivative of the concentration, or d[R]/dt=k. Note that the rate constant is found experimentally and is temperature and reaction specific.

Kelsey Warren 1I
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

Re: Rate Constant

Postby Kelsey Warren 1I » Tue Mar 05, 2019 8:11 pm

Something else to remember is that you can calculate k if the reaction rate, concentration of reactants, and the order of the reaction are known. Also, k is always positive and is the slope of the first order graph of ln[A] vs time.

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