Pseudo 1st order reaction


Moderators: Chem_Mod, Chem_Admin

Mya Majewski 1L
Posts: 89
Joined: Fri Sep 25, 2015 3:00 am

Pseudo 1st order reaction

Postby Mya Majewski 1L » Thu Mar 14, 2019 9:55 pm

What is a pseudo first order reaction and what homework problem is it used in?

Chem_Mod
Posts: 18889
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 716 times

Re: Pseudo 1st order reaction

Postby Chem_Mod » Thu Mar 14, 2019 11:23 pm

We use pseudo first order reactions when we are studying a reaction with multiple reactants with concentrations that could affect the rate law. For example if the reaction in question is A+B-->P we would design an experiment to find out how the rate changes with the concentrations of each reactant. The rate law=k' * [A]^n * [B]^m. To find [A], the [B] is made very high so that it remains relatively constant and the [A] is varied. We can then analyze the data like we did earlier in the section in order to calculate n. If n is 1 then the reaction is pseudo first order. Since we do not know the order for B, it is only pseudo first order not first order. We can then repeat the process for the other reactants.

Mya Majewski 1L
Posts: 89
Joined: Fri Sep 25, 2015 3:00 am

Re: Pseudo 1st order reaction

Postby Mya Majewski 1L » Fri Mar 15, 2019 12:09 am

okay, thank you! is there a homework problem like this?


Return to “Reaction Mechanisms, Reaction Profiles”

Who is online

Users browsing this forum: No registered users and 2 guests