Problem 50
Explain Le Châtelier's principle. How does this principle enable us to maximize the yields of desirable reactions and minimize the effect of undesirable ones?
Problem 51
Use Le Châtelier's principle to explain why the equilibrium vapor pressure of a liquid increases with increasing temperature.
Problem 52
List four factors that can shift the position of an equilibrium. Only one of these factors can alter the value of the equilibrium constant. Which one is it?
Problem 53
Does the addition of a catalyst have any effects on the position of an equilibrium?
Problem 54
Consider the following equilibrium system involving \(\mathrm{SO}_{2}, \mathrm{Cl}_{2},\) and \(\mathrm{SO}_{2} \mathrm{Cl}_{2}\) (sulfuryl dichloride): $$ \mathrm{SO}_{2}(g)+\mathrm{Cl}_{2}(g) \rightleftarrows \mathrm{SO}_{2} \mathrm{Cl}_{2}(g) $$ Predict how the equilibrium position would change if (a) \(\mathrm{Cl}_{2}\) gas were added to the system, (b) \(\mathrm{SO}_{2} \mathrm{Cl}_{2}\) were removed from the system, (c) \(\mathrm{SO}_{2}\) were removed from the system. The temperature remains constant in each case.
Problem 55
Heating solid sodium bicarbonate in a closed vessel establishes the following equilibrium: $$ 2 \mathrm{NaHCO}_{3}(s) \rightleftarrows \mathrm{Na}_{2} \mathrm{CO}_{3}(s)+\mathrm{H}_{2} \mathrm{O}(g)+\mathrm{CO}_{2}(g) $$ What would happen to the equilibrium position if (a) some of the \(\mathrm{CO}_{2}\) were removed from the system, (b) some solid \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) were added to the system, (c) some of the solid \(\mathrm{NaHCO}_{3}\) were removed from the system? The temperature remains constant.
Problem 56
Consider the following equilibrium systems: (a) \(\mathrm{A} \rightleftarrows 2 \mathrm{~B} \quad \Delta H^{\circ}=20.0 \mathrm{~kJ} / \mathrm{mol}\) (b) \(\mathrm{A}+\mathrm{B} \rightleftarrows \mathrm{C} \quad \Delta H^{\circ}=-5.4 \mathrm{~kJ} / \mathrm{mol}\) (c) \(\mathrm{A} \rightleftarrows \mathrm{B} \quad \Delta H^{\circ}=0.0 \mathrm{~kJ} / \mathrm{mol}\) Predict the change in the equilibrium constant \(K_{\mathrm{c}}\) that would occur in each case if the temperature of the reacting system were raised.
Problem 57
What effect does an increase in pressure have on each of the following systems at equilibrium? The temperature is kept constant, and, in each case, the reactants are in a cylinder fitted with a movable piston. (a) \(\mathrm{A}(s) \rightleftarrows 2 \mathrm{~B}(s)\) (b) \(2 \mathrm{~A}(l) \rightleftarrows \mathrm{B}(l)\) (c) \(\mathrm{A}(s) \rightleftarrows \mathrm{B}(g)\) (d) \(\mathrm{A}(g) \rightleftarrows \mathrm{B}(g)\) (e) \(\mathrm{A}(g) \rightleftarrows 2 \mathrm{~B}(g)\)
Problem 58
Consider the equilibrium: $$ 2 \mathrm{I}(g) \rightleftarrows \mathrm{I}_{2}(g) $$ What would be the effect on the position of equilibrium of (a) increasing the total pressure on the system by decreasing its volume, (b) adding \(\mathrm{I}_{2}\) to the reaction mixture, and (c) decreasing the temperature?
Problem 59
Consider the following equilibrium process: \(\mathrm{PCl}_{5}(g) \rightleftarrows \mathrm{PCl}_{3}(g)+\mathrm{Cl}_{2}(g) \quad \Delta H^{\circ}=92.5 \mathrm{~kJ} / \mathrm{mol}\) Predict the direction of the shift in equilibrium when (a) the temperature is raised, (b) more chlorine gas is added to the reaction mixture, (c) some \(\mathrm{PCl}_{3}\) is removed from the mixture, (d) the pressure on the gases is increased, (e) a catalyst is added to the reaction mixture.
