Chapter 13

What is a homogeneous catalyst? How does it function, in general terms?

What is the purpose of the catalytic converter that most automobiles use today? Is the catalyst heterogeneous or homogeneous?

What is the difference in meaning between the terms adsorption and absorption? Which one applies to heterogeneous catalysts?

Why should leaded gasoline not be used in cars equipped with catalytic converters?

The following data were collected for the decomposition of acetaldehyde. \(\mathrm{CH}_{3} \mathrm{CHO},\) (used in the manufacture of a variety of chemicals including perfumes, dyes, and plastics), into methane and carbon monoxide. The data were collected at \(535^{\circ} \mathrm{C}\). $$\mathrm{CH}_{3} \mathrm{CHO} \longrightarrow \mathrm{CH}_{4}+\mathrm{CO}$$ $$\begin{array}{cc}{\left[\mathrm{CH}_{3} \mathrm{CHO}\right]\left(\mathrm{mol}\mathrm{L}^{-1}\right)} & \text {Time (s) } \\ 0.200 & 0 \\\0.153 & 0.20 \times 10^{2} \\\0.124 & 0.40 \times 10^{2} \\\0.104 & 0.60 \times 10^{2} \\\0.090 & 0.80 \times 10^{2} \\\0.079 & 1.00 \times 10^{2} \\\0.070 & 1.20 \times 10^{2} \\\0.063 & 1.40 \times 10^{2} \\\0.058 & 1.60 \times 10^{2} \\\0.053 & 1.80 \times 10^{2} \\\0049 & 2.00 \times 10^{2} \\\\\hline\end{array}$$ Make a graph of concentration versus time and determine, using the tangent to the curve, the instantaneous rate of reaction of \(\mathrm{CH}_{3} \mathrm{CHO}\) after 60 seconds and after 120 seconds.

For the reaction, \(2 A+B \longrightarrow 3 C\), it was found that the rate of disappearance of \(B\) was \(0.30 \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}\). What were the rates of disappearance of \(A\) and the rate of appearance of \(C\) ?

In the reaction, \(3 \mathrm{H}_{2}+\mathrm{N}_{2} \longrightarrow 2 \mathrm{NH}_{3}\), how does the rate of disappearance of hydrogen compare to the rate of disappearance of nitrogen? How does the rate of appearance of \(\mathrm{NH}_{3}\) compare to the rate of disappearance of nitrogen?

In the combustion of hexane (a low-boiling component of gasoline),$$2 \mathrm{C}_{6} \mathrm{H}_{14}(g)+19 \mathrm{O}_{2}(g) \longrightarrow 12 \mathrm{CO}_{2}(g)+14 \mathrm{H}_{2} \mathrm{O}(g)$$ it was found that the rate of decrease of \(\mathrm{C}_{6} \mathrm{H}_{14}\) was \(1.20 \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}\) (a) What was the rate of reaction with respect to \(\mathrm{O}_{2} ?\) (b) What was the rate of formation of \(\mathrm{CO}_{2}\) ? (c) What was the rate of formation of \(\mathrm{H}_{2} \mathrm{O}\) ?

At a certain moment in the reaction, $$2 \mathrm{~N}_{2} \mathrm{O}_{5} \longrightarrow 4 \mathrm{NO}_{2}+\mathrm{O}_{2}$$ \(\mathrm{N}_{2} \mathrm{O}_{5}\), is decomposing at a rate of \(2.5 \times 10^{-6} \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}\). What are the rates of formation of \(\mathrm{NO}_{2}\) and \(\mathrm{O}_{2}\) ?

Consider the reaction, $$\mathrm{CH}_{3} \mathrm{Cl}(g)+3 \mathrm{Cl}_{2}(g) \longrightarrow \mathrm{CCl}_{4}(g)+3 \mathrm{HCl}(g)$$ (a) Express the rate of the reaction with respect to each of the reactants and products. (b) If the instantaneous rate of the reaction with respect to \(\mathrm{HCl}\) is \(0.029 \mathrm{M} \mathrm{s}^{-1}\), what is the instantaneous rate of the reaction?