2 NO(g) + 2 H2(g) --> N2(g) + 2 H2O(g)
Reactant Concentration(mol/L) and
Rate of Appearance of N2
[NO] [H2] (mol/L·s)
0.420 0.122 0.136
0.210 0.122 0.0339
0.210 0.244 0.0678
0.105 0.488 0.0339
What is the rate constant?
Here is what you need to do.
1. Determine order for NO.
2. Determine order for H2.
3. Determine k
rate = k(NO)^x(H2)^y
For the order of NO, divide equation 1 by 2. I get the order to be 2 for NO.
For the order of H2, divide equation 2 by 3. I get the order to be 1 for H2.
3. Use any equation, substitute rate, (NO) and (H2) and solve for k.
To determine the rate constant in this chemical reaction, we can use the rate equation:
rate = k[NO]^a[H2]^b
The exponents "a" and "b" represent the reaction orders for each reactant, and "k" is the rate constant.
From the given data, we can see that the rate of appearance of N2 is given at different reactant concentrations. By comparing the two experiments with constant concentrations of H2 (0.122 mol/L), we can determine the reaction order with respect to NO.
Let's compare the second and fourth experiments:
Experiment 2: [NO] = 0.210 mol/L, Rate = 0.0339 mol/L·s
Experiment 4: [NO] = 0.105 mol/L, Rate = 0.0339 mol/L·s
We can observe that when the concentration of NO is halved, the rate remains the same. This indicates that the reaction is zero-order with respect to NO.
Now, let's compare the first and third experiments where the concentration of NO is the same (0.210 mol/L), but the concentration of H2 is doubled from the third experiment to the first:
Experiment 1: [H2] = 0.122 mol/L, Rate = 0.136 mol/L·s
Experiment 3: [H2] = 0.244 mol/L, Rate = 0.0678 mol/L·s
We can see that when the concentration of H2 is doubled, the rate doubles. This indicates that the reaction is first-order with respect to H2.
Therefore, the rate equation for this reaction can be written as:
rate = k[NO]^0[H2]^1 = k[H2]
We now have the reaction order for each reactant. Since the reaction is first-order with respect to H2, the rate constant can be determined using one of the experiments where the concentration of H2 is the same (either 0.122 mol/L or 0.244 mol/L).
Let's use Experiment 1, where [H2] = 0.122 mol/L and the rate is 0.136 mol/L·s.
0.136 mol/L·s = k * 0.122 mol/L
k = 0.136 mol/L·s / 0.122 mol/L
k ≈ 1.115 L/mol·s
Therefore, the rate constant for this chemical reaction is approximately 1.115 L/mol·s.