## When to Use Avg. vs Instantaneous

$aR \to bP, Rate = -\frac{1}{a} \frac{d[R]}{dt} = \frac{1}{b}\frac{d[P]}{dt}$

lizzygaines1D
Posts: 52
Joined: Thu Jul 13, 2017 3:00 am

### When to Use Avg. vs Instantaneous

How would you be able to differentiate between using the unique average rate and the unique instantaneous rate?

Ethan-Van To Dis2L
Posts: 50
Joined: Fri Sep 29, 2017 7:05 am

### Re: When to Use Avg. vs Instantaneous

My TA told me that most of the time we would be using the instantaneous rate rather than the unique reaction rate because the instantaneous rate is more useful when determining the rate law.

K Stefanescu 2I
Posts: 68
Joined: Fri Sep 29, 2017 7:04 am

### Re: When to Use Avg. vs Instantaneous

Dr. Lavelle has said that the instantaneous rates are used most often, so I think we are to use them on most questions, unless the question explicitly requires that we use the average rates. Can anyone confirm this?

lizzygaines1D
Posts: 52
Joined: Thu Jul 13, 2017 3:00 am

### Re: When to Use Avg. vs Instantaneous

Okay I asked my TA and yes usually you should use the instantaneous unless told otherwise.

Sarah Sharma 2J
Posts: 33
Joined: Fri Sep 29, 2017 7:05 am

### Re: When to Use Avg. vs Instantaneous

Yes, instantaneous rate should always be used because we wish to know the rate of the reaction at any given moment .Instantaneous rate allows for us to solve that even with the changing slope as the rate that the reaction goes to products may not always be consistent, the rate can change.

Christina Bedrosian 1B
Posts: 33
Joined: Fri Sep 29, 2017 7:05 am

### Re: When to Use Avg. vs Instantaneous

you can also usually tell by what is given in the problem. for example if it doesn't give an order but gives you a rate then its most likely average rate instead of instantaneous