Reaction kinetics (AS): แบบฝึกหัด

What is the correct definition of activation energy, \( E_a \)?

The decomposition of a reactant X follows first-order kinetics. If the initial concentration of X is \(0.80 \text{ mol dm}^{-3}\) and its half-life is 20 minutes, what will the concentration of X be after 60 minutes?

In the oxidation of iodide ions by peroxodisulfate ions, \( S_2O_8^{2-} + 2I^- \to 2SO_4^{2-} + I_2 \), the reaction is catalysed by \( Fe^{2+}(aq) \).
Which set of equations correctly represents the homogeneous catalysis mechanism?

In the reaction between methane and chlorine, the first step is the homolytic fission of the \(Cl-Cl\) bond by ultraviolet light to form chlorine radicals. Which term best describes the minimum energy required for this specific step to occur effectively?

The reaction between hydrogen and nitrogen(II) oxide follows the rate equation: \( \text{rate} = k[NO]^2[H_2] \).
The following mechanism is proposed:
Step 1: \( 2NO \rightleftharpoons N_2O_2 \) (fast equilibrium)
Step 2: \( N_2O_2 + H_2 \to N_2O + H_2O \) (slow)
Step 3: \( N_2O + H_2 \to N_2 + H_2O \) (fast)
Why is the reaction second-order with respect to NO?

Define the term activation energy, \(E_a\), for a chemical reaction.

Using the Boltzmann distribution, explain qualitatively why a small increase in temperature leads to a significant increase in the rate constant, \( k \).

Describe the specific role of adsorption and desorption in the catalytic removal of oxides of nitrogen using a platinum-based catalytic converter in car engines.

(a) Define the term rate of reaction. [1]
(b) Use the collision theory to explain why increasing the temperature of a reaction mixture increases the rate of reaction. [3]<\/p>

The reaction between reactant X and reactant Y was studied at \(298\text{ K}\). The following experimental data were obtained:

(a) Deduce the order of reaction with respect to X and the order of reaction with respect to Y. Show your reasoning. [2]

(b) Construct the rate equation for this reaction. [1]

(c) Calculate the value of the rate constant, \(k\), for Experiment 1 and state its units. [2]