1. The following data was collected for the reaction between hydrogen and nitrogen monoxide. The time
recorded corresponds to a N2 concentration change of 5.3 x 10-4 M.
2H2(g) + 2NO(g) 2H2O(g) + N2(g)
Trial [H2], M [NO], M Time, s
1 0.01 0.02 74
2 0.02 0.02 37
3 0.01 0.01 296
a. Calculate the reaction rate for each of the three trials.
b. Determine the order of the reaction with respect to H2.
c. Determine the order of the reaction with respect to NO.
d. What is the rate law for this reaction?
e. What is the rate constant?
i'm not sure how to go about this process. I know they both increase by a rate of 2. But I don't know how to incorporate that.
To calculate the reaction rate for each trial, you need to use the formula:
Reaction rate = (Δ[H2]) / (Δt) = (2Δ[N2]) / (2Δt)
First, calculate the change in [N2] for each trial by subtracting the initial concentration from the final concentration:
Δ[N2] for trial 1 = 0 - 5.3 x 10^(-4) = -5.3 x 10^(-4) M
Δ[N2] for trial 2 = 0 - 5.3 x 10^(-4) = -5.3 x 10^(-4) M
Δ[N2] for trial 3 = 0 - 5.3 x 10^(-4) = -5.3 x 10^(-4) M
Now, calculate the change in time (Δt) for each trial using the given data:
Δt for trial 1 = 74 s
Δt for trial 2 = 37 s
Δt for trial 3 = 296 s
Now, substitute the values into the reaction rate formula to calculate the reaction rate for each trial:
Reaction rate for trial 1 = (2 x (-5.3 x 10^(-4))) / 74 = -1.432 x 10^(-5) M/s
Reaction rate for trial 2 = (2 x (-5.3 x 10^(-4))) / 37 = -2.865 x 10^(-5) M/s
Reaction rate for trial 3 = (2 x (-5.3 x 10^(-4))) / 296 = -1.075 x 10^(-6) M/s
To determine the order of the reaction with respect to H2, you can compare the reaction rates of trials 1 and 2 since the initial [NO] is the same:
Order with respect to H2 = (Reaction rate for trial 2) / (Reaction rate for trial 1)
= (-2.865 x 10^(-5) M/s) / (-1.432 x 10^(-5) M/s)
= 2
Similarly, to determine the order of the reaction with respect to NO, you can compare the reaction rates of trials 1 and 3 since the initial [H2] is the same:
Order with respect to NO = (Reaction rate for trial 3) / (Reaction rate for trial 1)
= (-1.075 x 10^(-6) M/s) / (-1.432 x 10^(-5) M/s)
= 0.075
Now that you have determined the reaction orders, the rate law can be written as:
Rate = k[H2]^2[NO]^0
Since the order with respect to NO is 0, [NO]^0 = 1, which simplifies to:
Rate = k[H2]^2
Finally, to find the rate constant k, you can pick any of the trials and use the rate law:
Rate for trial 1 = k (0.01)^2 (0.02)^0
-1.432 x 10^(-5) M/s = k (0.01)^2
k = -1.432 x 10^(-5) M/s / (0.01)^2
Now you can calculate the value of k.