## Unique Reaction Rates [ENDORSED]

Justin Chu 1G
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Joined: Thu Jul 13, 2017 3:00 am
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### Unique Reaction Rates

Such as in 15.3C and 15.5, I just wanted some clarification on what "unique" rate of a reaction means.

Nina Gautam 1K
Posts: 52
Joined: Fri Sep 29, 2017 7:04 am

### Re: Unique Reaction Rates

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.

Chem_Mod
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### Re: Unique Reaction Rates

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!

Magdalena Palavecino 1A
Posts: 54
Joined: Fri Sep 29, 2017 7:04 am

### Re: Unique Reaction Rates

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?

Anika_Patel_1G
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Joined: Fri Sep 29, 2017 7:06 am

### Re: Unique Reaction Rates  [ENDORSED]

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.

Leah Thomas 2E
Posts: 51
Joined: Fri Sep 29, 2017 7:06 am

### Re: Unique Reaction Rates

I'm still confused as to how we know when to use the instantaneous rate and the unique rates?

Peter Dis1G
Posts: 97
Joined: Fri Sep 29, 2017 7:04 am

### Re: Unique Reaction Rates

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')

Dang Lam
Posts: 55
Joined: Thu Jul 27, 2017 3:01 am

### Re: Unique Reaction Rates

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.

mayasinha1B
Posts: 70
Joined: Fri Sep 29, 2017 7:04 am

### Re: Unique Reaction Rates

I'm pretty sure the unique rate is the same for every reactant, so you just wouldn't take the stoichiometric coefficients into account.

Yeyang Zu 2J
Posts: 58
Joined: Fri Sep 29, 2017 7:06 am

### Re: Unique Reaction Rates

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

Abby Ellstrom 1I
Posts: 53
Joined: Fri Sep 29, 2017 7:04 am

### Re: Unique Reaction Rates

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.

Josh Moy 1H
Posts: 58
Joined: Thu Jul 13, 2017 3:00 am

### Re: Unique Reaction Rates

It's a unique reaction rate because its the same for all concentrations of reactants and products when multiplied by their stoichiometric coefficient.

Rishi Khettry 1L
Posts: 29
Joined: Fri Sep 29, 2017 7:05 am

### Re: Unique Reaction Rates

The unique reaction rate depends on the coefficients of the reaction

Michael Downs 1L
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Joined: Thu Jul 13, 2017 3:00 am

### Re: Unique Reaction Rates

Thanks!

Jordanmarshall
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Joined: Fri Apr 06, 2018 11:03 am

### Re: Unique Reaction Rates

what is the reaction rate??

Jocelyn1B
Posts: 27
Joined: Fri Apr 06, 2018 11:04 am

### Re: Unique Reaction Rates

The reaction rate is the measure of change in concentration of the reactants or the change in concentration of the products per unit time.

Zack Barta 3I
Posts: 27
Joined: Fri Sep 28, 2018 12:25 am

### Re: Unique Reaction Rates

What is the reaction rate?

Lucy Agnew 3E
Posts: 30
Joined: Fri Sep 28, 2018 12:26 am

### Re: Unique Reaction Rates

Arlene Linares 3A
Posts: 50
Joined: Fri Sep 28, 2018 12:25 am

### Re: Unique Reaction Rates

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

705022748
Posts: 26
Joined: Fri Sep 28, 2018 12:25 am

### Re: Unique Reaction Rates

Unique rate depends on the stoichiometric coefficient, but stays the same for all products and reactants in the reaction.

Zack Barta 3I
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Joined: Fri Sep 28, 2018 12:25 am

### Re: Unique Reaction Rates

Mariah Hill
Posts: 23
Joined: Fri Sep 28, 2018 12:28 am

### Re: Unique Reaction Rates

The unique rate has to do with the stoichiometric coefficients because it stays the same (proportionality)

705022748
Posts: 26
Joined: Fri Sep 28, 2018 12:25 am

### Re: Unique Reaction Rates

The unique rate stays constant for all reactants and depends on coefficients of the reaction.

105002507
Posts: 30
Joined: Fri Sep 28, 2018 12:15 am

### Re: Unique Reaction Rates

The unique rate depends on the stoichiometric coefficient & stays the same for all products and reactants

ran2000
Posts: 66
Joined: Fri Sep 28, 2018 12:15 am

### Re: Unique Reaction Rates

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.

riddhiduggal
Posts: 30
Joined: Fri Sep 28, 2018 12:21 am

### Re: Unique Reaction Rates

When do we use the instantaneous rate versus the unique rates?

Ashley P 4I
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Joined: Wed Nov 15, 2017 3:04 am

### Re: Unique Reaction Rates

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.

204929947
Posts: 76
Joined: Fri Apr 06, 2018 11:03 am

### Re: Unique Reaction Rates

what is the difference between the instantaneous rate and the unique rate law??

NicoJones_1B
Posts: 49
Joined: Fri Aug 09, 2019 12:16 am

### Re: Unique Reaction Rates

In what situations and types of problems will we have to use instanteous reaction rates?

AnayaArnold_3L
Posts: 56
Joined: Wed Sep 18, 2019 12:19 am

### Re: Unique Reaction Rates

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!

005162902
Posts: 102
Joined: Wed Sep 18, 2019 12:15 am

### Re: Unique Reaction Rates

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

Mitchell Koss 4G
Posts: 128
Joined: Sat Jul 20, 2019 12:17 am

### Re: Unique Reaction Rates

Combustion is also unique in that it will always have some reactants and some products that remain the same. (CO2, H2O)

AnayaArnold_3L
Posts: 56
Joined: Wed Sep 18, 2019 12:19 am

### Re: Unique Reaction Rates

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)

Maggie Eberhardt - 2H
Posts: 97
Joined: Sat Jul 20, 2019 12:16 am

### Re: Unique Reaction Rates

so in problems like 7A.3, we just take the unique rate and multiply it by the stoichiometric coefficient to determine the rate of each reactant/product right? just clarifying here, since I'm not 100% confident on the concept of unique rates