This question is about chemical equilibria in homogeneous gaseous systems.
State two essential characteristics of a system that has established dynamic equilibrium.
A homogeneous gas-phase equilibrium reaction is subjected to an increase in total pressure by reducing the volume of the reaction vessel. This change causes the equilibrium yield of the products to increase. State what can be deduced about the stoichiometry of the chemical equation for this equilibrium.
Gaseous compounds X\text{X}X and Y\text{Y}Y react to form gas Z\text{Z}Z according to the following equation: X(g)+2Y(g)⇌Z(g)\text{X(g)} + 2\text{Y(g)} \rightleftharpoons \text{Z(g)}X(g)+2Y(g)⇌Z(g)
Initially, 0.640 mol0.640\text{ mol}0.640 mol of X\text{X}X is mixed with 1.28 mol1.28\text{ mol}1.28 mol of Y\text{Y}Y in a sealed flask. Once equilibrium is established at temperature TTT, the total pressure in the flask is 360 kPa360\text{ kPa}360 kPa and the mixture is found to contain 0.240 mol0.240\text{ mol}0.240 mol of Z\text{Z}Z.
Calculate the amount, in moles, of X\text{X}X present at equilibrium. Hence, calculate the partial pressure, in kPa\text{kPa}kPa, of X\text{X}X in this equilibrium mixture.
Write an expression for the equilibrium constant (KpK_{\text{p}}Kp) for the reaction: X(g)+2Y(g)⇌Z(g)\text{X(g)} + 2\text{Y(g)} \rightleftharpoons \text{Z(g)}X(g)+2Y(g)⇌Z(g)
A different mixture containing gases X\text{X}X, Y\text{Y}Y, and Z\text{Z}Z is allowed to reach equilibrium at the same temperature TTT. Some of the equilibrium data for this mixture are presented in Table 1:
Table 1
| Substance | Equilibrium value |
|---|---|
| Partial pressure of X\text{X}X | 80.0 kPa80.0\text{ kPa}80.0 kPa |
| Partial pressure of Z\text{Z}Z | 16.0 kPa16.0\text{ kPa}16.0 kPa |
| KpK_{\text{p}}Kp | 5.00×10−6 kPa−25.00 \times 10^{-6}\text{ kPa}^{-2}5.00×10−6 kPa−2 |
Calculate the partial pressure, in kPa\text{kPa}kPa, of gas Y\text{Y}Y in this equilibrium mixture.
Using the value of KpK_{\text{p}}Kp given in Table 1, determine the value of KpK_{\text{p}}Kp for the reverse reaction at the same temperature TTT: Z(g)⇌X(g)+2Y(g)\text{Z(g)} \rightleftharpoons \text{X(g)} + 2\text{Y(g)}Z(g)⇌X(g)+2Y(g)
State the units for this new equilibrium constant.