Units for Rate Constants
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Units for Rate Constants
Is there an easy way to determine the units for rate constants for zeroth, first, and second-order reactions? Thank you!
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- Posts: 65
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Re: Units for Rate Constants
Basically the rate the reaction ((-1/a)(d[A]/dt)) is equal to mol x L^-1 x s ^-1. This rate is equal to the either k[A]^0, k[A]^1, k[A]^2 depending on whether or not the reaction is zeroth order, first order, or second order respectively. [A] represents the concentration of an unknown reactant and thus its units are mol x L^-1. The order of the reaction will be determined then by the power to which [A] is raised, which what you will divide the rate by as to solve for.
Ex: k= ((-1/a)(d[A]/dt)) / ([A]) = ( mol x L^-1 x s ^-1) / ( mol x L^-1) = s^-1
Ex: k= ((-1/a)(d[A]/dt)) / ([A]) = ( mol x L^-1 x s ^-1) / ( mol x L^-1) = s^-1
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Re: Units for Rate Constants
In the textbook there are questions with answers that have units in L per mol. Why is this and how do you generally determine the units for rate constants?
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Re: Units for Rate Constants
In the review session today, the TA said that using L is also acceptable. It's simply expanding molarity:)
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