Reversible reactions; dynamic equilibrium: แบบฝึกหัด

Consider the gaseous system at dynamic equilibrium in a sealed container at a constant temperature:
\( H_2(g) + I_2(g) \rightleftharpoons 2HI(g) \)
Which of the following observations provides the strongest evidence that the equilibrium is dynamic rather than static?

Consider the concentration-time graph for the gaseous equilibrium system: \( PCl_{5}(g) \rightleftharpoons PCl_{3}(g) + Cl_{2}(g) \). At time \( t_{1} \), the volume of the reaction vessel is suddenly decreased while keeping the temperature constant. Which of the following describes the behavior of the system immediately after \( t_{1} \) and the subsequent shift to a new equilibrium?

Consider the following gaseous equilibrium occurring at high temperature:
\( 4NH_{3}(g) + 5O_{2}(g) \rightleftharpoons 4NO(g) + 6H_{2}O(g) \)
What is the unit of the equilibrium constant, \( K_{c} \), for this reaction?

A mixture of \( SO_{2}(g) \), \( O_{2}(g) \), and \( SO_{3}(g) \) is at equilibrium in a container of volume \( V \) at temperature \( T \). The reaction is represented by:
\( 2SO_{2}(g) + O_{2}(g) \rightleftharpoons 2SO_{3}(g) \quad \Delta H = -198 \, kJ \, mol^{-1} \)
If the volume of the container is increased to \( 2V \) and the temperature is simultaneously increased to \( T + 50 \, K \), which of the following will occur once a new equilibrium is established?

The decomposition of solid ammonium carbamate follows the equation below:
\( NH_{2}COONH_{4}(s) \rightleftharpoons 2NH_{3}(g) + CO_{2}(g) \)
A sample of the solid is placed in an evacuated, sealed container at a constant temperature. Which of the following statements is CORRECT when the system reaches dynamic equilibrium?

Consider the reversible gaseous reaction: \(2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)\), where the forward reaction is exothermic.

Predict and explain the combined effect on the equilibrium yield of sulfur trioxide (\(SO_3\)) and the value of the equilibrium constant (\(K_c\)) if the temperature is simultaneously decreased and the total pressure of the system is increased by reducing its volume.

Phosgene (\(\text{COCl}_2\)) is a vital industrial precursor for the synthesis of polyurethanes and polycarbonates. The production of phosgene involves the following reversible reaction:

\(\text{CO(g)} + \text{Cl}_2\text{(g)} \rightleftharpoons \text{COCl}_2\text{(g)}\)

In a laboratory investigation, 0.40 mol of \(\text{CO(g)}\) and 0.80 mol of \(\text{Cl}_2\text{(g)}\) were introduced into an evacuated sealed container of volume 2.0 \(\text{dm}^3\) at a constant temperature \(T_1\). When the system reached equilibrium, the concentration of \(\text{COCl}_2\text{(g)}\) was found to be 0.15 \(\text{mol dm}^{-3}\).

(a) Calculate the equilibrium constant \(K_c\) for this reaction at \(T_1\), stating its units. (3 marks)

(b) If the volume of the reaction container was suddenly reduced to 1.0 \(\text{dm}^3\) while maintaining the temperature at \(T_1\), explain the effect on the equilibrium yield of \(\text{COCl}_2\text{(g)}\) using Le Chatelier's Principle. (2 marks)

(c) The formation of phosgene is an exothermic process (\(\Delta H < 0\)). The temperature of the system was subsequently changed to a new temperature \(T_2\). At the new equilibrium, it was observed that the percentage decomposition of \(\text{COCl}_2\text{(g)}\) had increased. State and explain whether \(T_2\) is higher or lower than \(T_1\), and predict how the value of \(K_c\) would change compared to its value at \(T_1\). (3 marks)

The industrial synthesis of methanol involves the following reversible reaction:

\(\text{CO(g)} + 2\text{H}_2\text{(g)} \rightleftharpoons \text{CH}_3\text{OH(g)}\)     \(\Delta H = -91 \text{ kJ mol}^{-1}\)

In a laboratory investigation, 2.00 mol of \(\text{CO(g)}\) and 5.00 mol of \(\text{H}_2\text{(g)}\) were introduced into an evacuated sealed container of volume 2.00 \(\text{dm}^3\) at a constant temperature \(T_1\). When the system reached equilibrium, the amount of \(\text{CH}_3\text{OH(g)}\) was found to be 0.80 mol.

(a) Calculate the equilibrium constant \(K_c\) for the reaction at temperature \(T_1\), stating its units. (4 marks)

(b) If the volume of the reaction container was suddenly reduced to 1.00 \(\text{dm}^3\) while maintaining the temperature at \(T_1\), explain the effect on the equilibrium yield of \(\text{CH}_3\text{OH(g)}\) using Le Chatelier's Principle. (2 marks)

(c) The temperature of the system was subsequently increased from \(T_1\) to a higher temperature \(T_2\). State and explain how the value of the equilibrium constant \(K_c\) would change compared to its value at \(T_1\). (2 marks)