Reaction rate

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Cecilia Jardon 1I
Posts: 74
Joined: Fri Sep 28, 2018 12:16 am

Reaction rate

Postby Cecilia Jardon 1I » Tue Mar 12, 2019 9:39 pm

S2O8 ^-2 + 3I- --> 2SO4^2- + I3-
Rate of consumption of S2O8^2- = k [S2O8^2-] [I-]
The book says that doubling either the S2O8 ^2- ion concentration or the I- ion concentration doubles the reaction rate. I am confused as to what exactly the reaction rate is. Is it k? or is it the whole reaction: Rate of consumption of S2O8^2- = k [S2O8^2-] [I-]? Can someone help ? Thanks.

Steven Garcia 1H
Posts: 79
Joined: Fri Sep 28, 2018 12:16 am

Re: Reaction rate

Postby Steven Garcia 1H » Tue Mar 12, 2019 9:45 pm


k is just the rate constant, whereas the whole expression represents the rate of the reaction.

Another way to think about it is that the problem mentions the rate doubles as a result of doubling the concentration. Rate constants for a given reaction are CONSTANT, they do not change for a given reaction. Therefore, k can not be represent the reaction rate!

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