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Unique Reaction Rates

Posted: Wed Feb 28, 2018 5:21 pm
by Justin Chu 1G
Such as in 15.3C and 15.5, I just wanted some clarification on what "unique" rate of a reaction means.

Re: Unique Reaction Rates

Posted: Wed Feb 28, 2018 5:52 pm
by Nina Gautam 1K
It's a unique reaction rate because it is the same for all concentrations of reactants and products when it is multiplied by their stoichiometric coefficient. The species doesn't need to be specified when writing a unique rate.

Re: Unique Reaction Rates

Posted: Thu Mar 01, 2018 7:38 pm
by Chem_Mod
I will discuss this in class tomorrow.

AVERAGE RATE = (CONC(t2) − CONC(t1))/(t2 −t1) = ∆CONC/∆t

INSTANTANEOUS RATE = −(d[R])/dt
OR
INSTANTANEOUS RATE = (d[P])/dt

AVERAGE & INSTANTANEOUS RATES CAN BE DIFFERERENT FOR THE INDIVIDUAL R & P.
THINK OF THEM AS THE EXPERIMENTALLY MEASURED RATES (COLLECTED DATA) OVER LONG TIME INTERVALS (∆) OR SHORT TIME INTERVALS (d).

UNLIKE THE UNIQUE RATE WHICH IS CALCULATED AND IS THE SAME FOR ALL R & P IN THAT ‘UNIQUE’ REACTION WHERE:

UNIQUE RATE = −1/a (d[A])/dt = 1/b (d[B])/dt = 1/c (d[C])/dt

IN THE REACTION: a A ---> b B + c C

Hopefully this clarifies.

Stay warm and see you in class!

Re: Unique Reaction Rates

Posted: Sat Mar 03, 2018 12:41 pm
by Magdalena Palavecino 1A
Does this mean that even if all the stoichiometric coefficients were different, because of the concentrations of each species then all rates would be the same? And does unique rate refer to the equality of all rates or of one species only?

Re: Unique Reaction Rates  [ENDORSED]

Posted: Sat Mar 03, 2018 9:19 pm
by Anika_Patel_1G
If all of the stoichiometric coefficients were different, the unique rate can still be the same using any of them to calculate it because we are multiplying the (change in concentration/change in time) by 1/coefficient. This therefore allows us to calculate the unique rate using any of the species in the reaction. The unique rate refers to the one rate calculated using one of the species. The equality formula is just to show that it does not matter which one you choose as long as you multiple by 1/coefficient and negate the equation if it is a reactant.

Re: Unique Reaction Rates

Posted: Sun Mar 04, 2018 9:55 pm
by Leah Thomas 2E
I'm still confused as to how we know when to use the instantaneous rate and the unique rates?

Re: Unique Reaction Rates

Posted: Sun Mar 04, 2018 10:35 pm
by Peter Dis1G
I think instantaneous rate is the general but more accurate measure of the rate of change of concentration, and unique rate is like the instantaneous rate of individual species. (so the name 'unique')

Re: Unique Reaction Rates

Posted: Tue Mar 06, 2018 1:02 pm
by Dang Lam
Anika_Patel_1G wrote:If all of the stoichiometric coefficients were different, the unique rate can still be the same using any of them to calculate it because we are multiplying the (change in concentration/change in time) by 1/coefficient. This therefore allows us to calculate the unique rate using any of the species in the reaction. The unique rate refers to the one rate calculated using one of the species. The equality formula is just to show that it does not matter which one you choose as long as you multiple by 1/coefficient and negate the equation if it is a reactant.

Thank you so much! your response is very helpful

Re: Unique Reaction Rates

Posted: Wed Mar 07, 2018 11:38 am
by mayasinha1B
I'm pretty sure the unique rate is the same for every reactant, so you just wouldn't take the stoichiometric coefficients into account.

Re: Unique Reaction Rates

Posted: Sun Mar 11, 2018 1:32 pm
by Yeyang Zu 2J
I will say the rate of a chemical reaction is the change in concentration over the change in time and is a metric of the "speed" at which a chemical reactions occurs.
And Unique rate is the rate occurs per unit of each molecules

Re: Unique Reaction Rates

Posted: Mon Mar 12, 2018 7:30 pm
by Abby Ellstrom 1I
A unique rate is the same for all of the materials in the reaction (products and reactants) because it multiplies the change in substance by one over its coefficient.

Re: Unique Reaction Rates

Posted: Tue Mar 13, 2018 8:29 pm
by Josh Moy 1H
It's a unique reaction rate because its the same for all concentrations of reactants and products when multiplied by their stoichiometric coefficient.

Re: Unique Reaction Rates

Posted: Tue Mar 13, 2018 11:08 pm
by Rishi Khettry 1L
The unique reaction rate depends on the coefficients of the reaction

Re: Unique Reaction Rates

Posted: Fri Mar 16, 2018 8:47 pm
by Michael Downs 1L
Thanks!

Re: Unique Reaction Rates

Posted: Fri Apr 27, 2018 3:28 pm
by Jordanmarshall
what is the reaction rate??

Re: Unique Reaction Rates

Posted: Sun Apr 29, 2018 4:40 pm
by Jocelyn1B
The reaction rate is the measure of change in concentration of the reactants or the change in concentration of the products per unit time.

Re: Unique Reaction Rates

Posted: Tue Oct 23, 2018 1:15 pm
by Zack Barta 3I
What is the reaction rate?

Re: Unique Reaction Rates

Posted: Fri Oct 26, 2018 9:51 am
by Lucy Agnew 3E
These explanations were very helpful! Totally forgot about this !

Re: Unique Reaction Rates

Posted: Thu Nov 08, 2018 3:39 pm
by Arlene Linares 3A
Chem_Mod wrote:I will discuss this in class tomorrow.

AVERAGE RATE = (CONC(t2) − CONC(t1))/(t2 −t1) = ∆CONC/∆t

INSTANTANEOUS RATE = −(d[R])/dt
OR
INSTANTANEOUS RATE = (d[P])/dt

AVERAGE & INSTANTANEOUS RATES CAN BE DIFFERERENT FOR THE INDIVIDUAL R & P.
THINK OF THEM AS THE EXPERIMENTALLY MEASURED RATES (COLLECTED DATA) OVER LONG TIME INTERVALS (∆) OR SHORT TIME INTERVALS (d).

UNLIKE THE UNIQUE RATE WHICH IS CALCULATED AND IS THE SAME FOR ALL R & P IN THAT ‘UNIQUE’ REACTION WHERE:

UNIQUE RATE = −1/a (d[A])/dt = 1/b (d[B])/dt = 1/c (d[C])/dt

IN THE REACTION: a A ---> b B + c C

Hopefully this clarifies.

Stay warm and see you in class!



Thank you for the information

Re: Unique Reaction Rates

Posted: Thu Nov 15, 2018 10:54 am
by 705022748
Unique rate depends on the stoichiometric coefficient, but stays the same for all products and reactants in the reaction.

Re: Unique Reaction Rates

Posted: Sun Nov 25, 2018 3:18 pm
by Zack Barta 3I
Very Helpful!

Re: Unique Reaction Rates

Posted: Mon Nov 26, 2018 12:12 am
by Mariah Hill
The unique rate has to do with the stoichiometric coefficients because it stays the same (proportionality)

Re: Unique Reaction Rates

Posted: Mon Nov 26, 2018 12:46 am
by 705022748
The unique rate stays constant for all reactants and depends on coefficients of the reaction.

Re: Unique Reaction Rates

Posted: Sun Dec 02, 2018 1:02 pm
by 105002507
The unique rate depends on the stoichiometric coefficient & stays the same for all products and reactants

Re: Unique Reaction Rates

Posted: Sat Mar 09, 2019 7:10 pm
by ran2000
The unique reaction rate is defined as the rate of the increase in product concentration or the rate in decrease of product concentration divided by the stoichiometric coefficient.

Re: Unique Reaction Rates

Posted: Fri Mar 15, 2019 10:51 pm
by riddhiduggal
When do we use the instantaneous rate versus the unique rates?

Re: Unique Reaction Rates

Posted: Sat Mar 16, 2019 1:21 pm
by Ashley P 4I
riddhiduggal wrote:When do we use the instantaneous rate versus the unique rates?

I am also still really confused on this. If I find out, I’ll let you know.

Re: Unique Reaction Rates

Posted: Sat Mar 16, 2019 11:13 pm
by 204929947
what is the difference between the instantaneous rate and the unique rate law??

Re: Unique Reaction Rates

Posted: Sun Oct 13, 2019 11:20 am
by NicoJones_1B
In what situations and types of problems will we have to use instanteous reaction rates?

Re: Unique Reaction Rates

Posted: Sun Oct 27, 2019 10:06 pm
by AnayaArnold_3L
Thank you for clarifying!
Chem_Mod wrote:I will discuss this in class tomorrow.

AVERAGE RATE = (CONC(t2) − CONC(t1))/(t2 −t1) = ∆CONC/∆t

INSTANTANEOUS RATE = −(d[R])/dt
OR
INSTANTANEOUS RATE = (d[P])/dt

AVERAGE & INSTANTANEOUS RATES CAN BE DIFFERERENT FOR THE INDIVIDUAL R & P.
THINK OF THEM AS THE EXPERIMENTALLY MEASURED RATES (COLLECTED DATA) OVER LONG TIME INTERVALS (∆) OR SHORT TIME INTERVALS (d).

UNLIKE THE UNIQUE RATE WHICH IS CALCULATED AND IS THE SAME FOR ALL R & P IN THAT ‘UNIQUE’ REACTION WHERE:

UNIQUE RATE = −1/a (d[A])/dt = 1/b (d[B])/dt = 1/c (d[C])/dt

IN THE REACTION: a A ---> b B + c C

Hopefully this clarifies.

Stay warm and see you in class!

Re: Unique Reaction Rates

Posted: Mon Oct 28, 2019 11:51 am
by 005162902
Peter Dis1G wrote:I think instantaneous rate is the general but more accurate measure of the rate of change of concentration, and unique rate is like the instantaneous rate of individual species. (so the name 'unique')


unique rate is is the same for all reactants because of its coefficients

Re: Unique Reaction Rates

Posted: Mon Nov 04, 2019 3:41 pm
by Mitchell Koss 4G
Combustion is also unique in that it will always have some reactants and some products that remain the same. (CO2, H2O)

Re: Unique Reaction Rates

Posted: Mon Nov 11, 2019 7:31 pm
by AnayaArnold_3L
Thank you
Mitchell Koss 4G wrote:Combustion is also unique in that it will always have some reactants and some products that remain the same. (CO2, H2O)