The reaction of NO and O2 produces NO2.
2 NO(g) + O2(g) „_ 2 NO2(g)
The reaction is second-order with respect to NO(g) and first-order with respect to O2(g). At a given temperature, the rate constant, k, equals 4.7 x 10^2 M^¡V2s^¡V1. What is the rate of reaction when the initial concentrations of NO and O2 are 0.025 M and 0.015 M, respectively?
Show your work: I thought it was
1/0.025-1/0.015=4.7 x 10^2 M^¡V2s^¡V1
but that is not right b/c the answer is 4.4 x 10^-3 M/s
You're trying to solve the problem wrong. Since one is first order and the other is second order, that equation won't work; besides, you have only one concn. What you want to use is the rate equation of
rate = k(NO)^2(O2)
Plug in k, NO, and O2 and calculate rate. 4.4E-3 is the right answer.
The rate constant for a first-order reaction is 1.6 × 10–2 s–1 at 664 K and 3.9 × 10–2 s–1 at 866 K. What is the activation energy? (R = 8.314 J/K⋅mol)
Well, it seems like you've gotten yourself in a bit of a reaction mix-up! Let's try to sort things out.
First of all, to find the rate of reaction, we need to use the rate law expression, which is determined from the balanced equation. In this case, the rate law can be written as:
rate = k[NO]^2[O2]
where [NO] is the concentration of NO and [O2] is the concentration of O2.
You're given the rate constant, k, as 4.7 x 10^2 M^-2s^-1, and the initial concentrations of NO and O2 as 0.025 M and 0.015 M, respectively.
To find the rate of reaction, we can substitute these values into the rate law expression:
rate = (4.7 x 10^2 M^-2s^-1)(0.025 M)^2(0.015 M)
Calculating this gives us the correct rate of reaction as 4.4 x 10^-3 M/s.
So, the correct expression is:
rate = (4.7 x 10^2 M^-2s^-1)(0.025 M)^2(0.015 M) = 4.4 x 10^-3 M/s
Looks like there's no clowning around in chemistry!
To calculate the rate of reaction, we need to use the rate equation which is given by:
rate = k * [NO]^2 * [O2]
Given that the reaction is second-order with respect to NO and first-order with respect to O2, the exponents in the rate equation represent the stoichiometric coefficients of the reactants.
Substituting the given values into the rate equation, we have:
rate = (4.7 x 10^2 M^-2 s^-1) * (0.025 M)^2 * (0.015 M)
Simplifying the expression:
rate = (4.7 x 10^2) * (0.025)^2 * (0.015)
rate = (4.7 x 10^2) * (0.000625) * (0.015)
rate = 4.4 x 10^-3 M/s
Therefore, the rate of reaction when the initial concentrations of NO and O2 are 0.025 M and 0.015 M, respectively, is 4.4 x 10^-3 M/s.
The incorrect calculation you provided (1/0.025 - 1/0.015) is not the correct expression for determining the rate of reaction. The rate equation must be used as shown above.