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Caitlin Mispagel 1D
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Joined: Tue Oct 10, 2017 7:13 am


Postby Caitlin Mispagel 1D » Tue Mar 06, 2018 5:08 pm

Do coefficients have any effect on the rate law?

Rachel Brown 3A
Posts: 52
Joined: Fri Sep 29, 2017 7:06 am

Re: Coefficients

Postby Rachel Brown 3A » Tue Mar 06, 2018 5:12 pm

Coefficients play a role in the unique rate law that states where aA --> bB, the rate = (-1/a)(dA/dt) = (1/b)(dB/dt). Because of this, you can identify how and individual product/reaction rate compares to another based on it's coefficient as shown in 15.1.

Christine Wastila 1H
Posts: 61
Joined: Fri Sep 29, 2017 7:04 am

Re: Coefficients

Postby Christine Wastila 1H » Tue Mar 06, 2018 5:17 pm

They do not affect the rate law as written: rate=k[A]order (i.e. you would not input different values than those given for concentration or oder because of the stoichiometric coefficients).

Posts: 30
Joined: Sat Jul 22, 2017 3:00 am

Re: Coefficients

Postby Daniisaacson2F » Tue Mar 06, 2018 8:44 pm

Coefficients do not determine the order of the reaction, they just matter when it says the concentration of the products vs reactants and you have to multiply by a coefficient to keep the rate consistent.

Alex Nechaev 1I
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

Re: Coefficients

Postby Alex Nechaev 1I » Tue Mar 06, 2018 10:40 pm

Coefficients do affect unique rates, but not the general rate law or determining formation or consumption of products or reactants.

Morgan Baxter 1E
Posts: 50
Joined: Thu Jul 27, 2017 3:00 am

Re: Coefficients

Postby Morgan Baxter 1E » Tue Mar 06, 2018 10:55 pm

The only time coefficients can be used in order to determine the order of a reaction is when it is an elementary reaction.

Amanda Wu 2C
Posts: 31
Joined: Sat Jul 22, 2017 3:00 am

Re: Coefficients

Postby Amanda Wu 2C » Wed Mar 07, 2018 4:13 pm

As others have mentioned, coefficients affect the unique reaction rate or the rate law for elementary steps of a reaction. In the case of the unique reaction rate, the stoichiometric coefficients are in the denominator of the rate of consumption/formation of a reactant/product to get the unique rate for the reaction (a negative is also included when using reactants so the rate becomes positive). In terms of the rate laws for elementary steps, the coefficients are used as the powers (order) corresponding to each reactant concentration. However, you can't use the coefficients to generalize a reaction's order in its rate law otherwise.

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