Question

question 22 (1 point)
fatima is studying the following reaction:
2 nh₃(aq) ⇌ n₂(g) + 3 h₂(g)
she makes a graph of the initial rate vs. the initial concentration of nh₃ and finds the shape to be a curved line. the rate law is therefore most likely:
r = knh₃
r = knh₃²
r = knh₃n₂
r = nh₃²
r = nh₃²n₂
question 23 (1 point)

Explanation:

Step1: Analyze the general form of rate law

The general form of rate law is \(r = k[A]^n\), where \(n\) is the order of the reaction with respect to reactant \(A\).

Step2: Consider the relationship between rate and concentration for different orders

• For a first - order reaction (\(n = 1\)), \(r=k[A]\), the graph of rate (\(r\)) vs concentration (\([A]\)) is a straight line (\(y = mx\) form, where \(y=r\), \(m = k\), \(x = [A]\)).
• For a second - order reaction (\(n = 2\)), \(r = k[A]^2\), the graph of rate (\(r\)) vs concentration (\([A]\)) is a curved line (\(y=mx^{2}\) form).
• Option \(r = k[NH_3][N_2]\): Since \(N_2\) is a product, it should not be in the rate law (rate law is expressed in terms of reactants only for an elementary reaction, and for non - elementary reactions, we find rate law from experimental data. Here the experiment is about the effect of \(NH_3\) concentration on rate).
• Option \(r=[NH_3]^2\): Missing the rate constant \(k\). Rate law must have the rate constant.
• Option \(r = [NH_3]^2[N_2]\): \(N_2\) is a product and should not be in the rate law, and also missing the rate constant \(k\).

Answer:

\(r = k[NH_3]^2\)