Determine the overall orders of the reactions to which the following rate laws apply:
a. rate = k[NO2]^2
b. rate = k
c. rate = k[H2][Br2]^1/2
d. rate = k[NO]^2[O2]
I think the answers are:
a. Second Order
b. Zero Order
c. First Order for H2 and One-half order for Br2
d. Second Order for NO and first order for O2
I am not entirely sure, so I just want to check.
Thanks!
a and b are correct. You have the c and d correct for the order of each; however, the problem asks for the overall order. Therefore, c is 1.5 (1 + 1/2 = 1-1/2) and d is 3. The overall order is the sum of the individual orders.
Thank You! :)
Your answers are correct, except for one minor correction in part c.
a. The rate law rate = k[NO2]^2 is a second-order reaction because the reaction rate is directly proportional to the square of the concentration of NO2.
b. The rate law rate = k is a zero-order reaction because the reaction rate is independent of the concentration of the reactant.
c. The rate law rate = k[H2][Br2]^1/2 is a first-order reaction with respect to H2, but the term [Br2]^1/2 means that the overall order for Br2 is 1/2. So the correct answer is first order for H2 and one-half order for Br2.
d. The rate law rate = k[NO]^2[O2] is a second-order reaction with respect to NO because it is squared, and it is also first order with respect to O2. Hence, the overall order is second order for NO and first order for O2.
So, just a minor correction in part c. Other than that, your answers are correct!
To determine the overall order of a reaction, you need to add up the exponents of the concentration terms in the rate law.
a. The rate law is rate = k[NO2]^2. Since the exponent of [NO2] is 2, the overall order is 2.
b. The rate law is rate = k. There are no concentration terms in the rate law, so the concentration exponents must be 0. The overall order is 0, also known as a zero-order reaction.
c. The rate law is rate = k[H2][Br2]^1/2. The exponents of [H2] and [Br2] are 1 and 1/2, respectively. Adding them up, the overall order is 1 + 1/2 = 3/2, or 1.5.
d. The rate law is rate = k[NO]^2[O2]. The exponents of [NO] and [O2] are both 2. Adding them up, the overall order is 2 + 2 = 4.
Your answers are incorrect for parts c and d. The correct answers are:
c. The overall order is 1 + 1/2 = 1.5, which is first order for H2 and one-half order for Br2.
d. The overall order is 2 + 1 = 3, which is second order for NO and first order for O2.
So, the correct answers are:
a. Second order
b. Zero order
c. First order for H2 and one-half order for Br2
d. Second order for NO and first order for O2