Unique Reaction Rates [ENDORSED]
Moderators: Chem_Mod, Chem_Admin
-
- Posts: 52
- Joined: Thu Jul 13, 2017 2:00 am
- Been upvoted: 1 time
Unique Reaction Rates
Such as in 15.3C and 15.5, I just wanted some clarification on what "unique" rate of a reaction means.
-
- Posts: 52
- Joined: Fri Sep 29, 2017 6:04 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.
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!
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!
-
- Posts: 54
- Joined: Fri Sep 29, 2017 6:04 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?
-
- Posts: 32
- Joined: Fri Sep 29, 2017 6:06 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.
-
- Posts: 51
- Joined: Fri Sep 29, 2017 6:06 am
Re: Unique Reaction Rates
I'm still confused as to how we know when to use the instantaneous rate and the unique rates?
-
- Posts: 97
- Joined: Fri Sep 29, 2017 6:04 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')
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.
Thank you so much! your response is very helpful
-
- Posts: 70
- Joined: Fri Sep 29, 2017 6:04 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.
-
- Posts: 58
- Joined: Fri Sep 29, 2017 6:06 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
And Unique rate is the rate occurs per unit of each molecules
-
- Posts: 53
- Joined: Fri Sep 29, 2017 6:04 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.
-
- Posts: 58
- Joined: Thu Jul 13, 2017 2:00 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.
-
- Posts: 29
- Joined: Fri Sep 29, 2017 6:05 am
-
- Posts: 16
- Joined: Fri Apr 06, 2018 10:03 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.
-
- Posts: 27
- Joined: Thu Sep 27, 2018 11:25 pm
-
- Posts: 30
- Joined: Thu Sep 27, 2018 11:26 pm
-
- Posts: 50
- Joined: Thu Sep 27, 2018 11:25 pm
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
Re: Unique Reaction Rates
Unique rate depends on the stoichiometric coefficient, but stays the same for all products and reactants in the reaction.
-
- Posts: 27
- Joined: Thu Sep 27, 2018 11:25 pm
-
- Posts: 23
- Joined: Thu Sep 27, 2018 11:28 pm
Re: Unique Reaction Rates
The unique rate has to do with the stoichiometric coefficients because it stays the same (proportionality)
Re: Unique Reaction Rates
The unique rate stays constant for all reactants and depends on coefficients of the reaction.
Re: Unique Reaction Rates
The unique rate depends on the stoichiometric coefficient & stays the same for all products and reactants
Who is online
Users browsing this forum: No registered users and 2 guests