反應速率與平衡導論：練習題

Which of the following statements best describes a chemical system in a state of dynamic equilibrium?

In the industrial production of methanol, the following equilibrium is established:
\(CO(g) + 2H_2(g) \rightleftharpoons CH_3OH(g)\)    \(\Delta H < 0\)
Industrial conditions often involve high pressures and a copper-based catalyst. Why is a pressure of about \(50-100\text{ atm}\) used rather than atmospheric pressure?

The reaction between hydrogen and iodine is represented by:
\(H_2(g) + I_2(g) \rightleftharpoons 2HI(g)\)    \(\Delta H = -9.4\text{ kJ mol}^{-1}\)
A sealed container at equilibrium is compressed to half its original volume at constant temperature. Which of the following is true for the new equilibrium state?

In terms of collision theory, what is the activation energy (\(E_a\)) of a chemical reaction?

Consider the reaction of nitrogen dioxide to form dinitrogen tetroxide:
\(2NO_2(g) \rightleftharpoons N_2O_4(g)\)    \(\Delta H = -57.2\text{ kJ mol}^{-1}\)
A sample of this gas mixture is held in a sealed container at equilibrium. If the temperature of the system is increased while keeping the volume constant, which of the following describes the changes to the system?

State two essential conditions for a chemical system to exist in a state of dynamic equilibrium.

The production of sulfur trioxide is represented by the equation:
\(2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)\)     \(\Delta H = -197 \text{ kJ mol}^{-1}\)
Predict and justify the effect of increasing the pressure on the equilibrium yield of \(SO_3\).

On a reaction profile diagram for an exothermic reaction, describe how the curve changes when a heterogeneous catalyst is introduced, and explain this change in terms of the activation energy \(E_a\).

(a) Define the term activation energy, \(E_a\).
(b) Use the collision theory to explain how an increase in the concentration of a reactant affects the rate of a chemical reaction.

The distribution of molecular energies in a gas at a temperature \(T_1\) is shown by a Maxwell-Boltzmann distribution curve.
(a) Describe the changes to the shape of this curve when the temperature is increased to \(T_2\).
(b) Explain, by referring to the area under the curve, why a small increase in temperature leads to a large increase in the rate of reaction.