Equilibrium constant Kp

This question is about some gas mixtures at equilibrium.

This reaction can be used to make hydrogen.

A mixture of 2.00 mol of H₂O(g) and 2.00 mol of CO(g) is allowed to reach equilibrium at a constant temperature in a 20 dm³ container. At equilibrium, there are 0.92 mol of H₂(g).

Calculate the mole fraction of H₂(g) in the equilibrium mixture.

State why the equilibrium constant (K_p) for this reaction has no units.

The temperature of the equilibrium mixture formed in Question 04.1 is increased.

How does the amount of H₂(g) change when the new position of equilibrium is reached?

Tick (✓) one box.

Ethanol can be made from ethene and steam.

Table 2 shows the mole fractions of each of the gases in an equilibrium mixture at 6000 kPa

Give an expression for K_p for this reaction.

Calculate the value of K_p at 6000 kPa

State the units.

State the effect, if any, of an increase in volume of the container on the value of K_p for this reaction at a constant temperature.

Nitrogen dioxide decomposes at a high temperature.

A 0.317 mol sample of nitrogen dioxide is placed in a sealed flask and heated at a constant temperature until equilibrium is reached.

At equilibrium, the flask contains 0.120 mol of oxygen.

Calculate the mole fraction of each substance at equilibrium.

The total pressure in the flask in Question 04.1 is 120 kPa at equilibrium.

Calculate the partial pressure, in kPa, of NO₂

If you were unable to answer Question 04.1 you should assume that the mole fraction of NO₂ is 0.380. This is not the correct answer.

Table 1 shows the mole fractions of the three gases in a different equilibrium mixture.

For this equilibrium mixture, K_p = 59.7 kPa

Give an expression for K_p for this reaction.

Use your expression and the data in Table 1 to calculate the total pressure, in kPa, in the flask.

The equilibrium mixture in Question 04.3 is compressed into a smaller volume.

Deduce the effect, if any, of this change on the equilibrium yield of oxygen and on the

Effect on yield of oxygen

The equilibrium mixture in Question 04.3 is allowed to reach equilibrium at a lower temperature.

Explain why the equilibrium yield of oxygen decreases.

The equation for the complete combustion of butane is

What is the mole fraction of butane in a mixture of butane and oxygen with the minimum amount of oxygen needed for complete combustion?

This question is about equilibria.

Give two features of a reaction in dynamic equilibrium.

A gas-phase reaction is at equilibrium. When the pressure is increased the yield of product decreases.

State what can be deduced about the chemical equation for this equilibrium.

Carbon monoxide and hydrogen react to form methanol.

0.430 mol of carbon monoxide is mixed with 0.860 mol of hydrogen. At equilibrium, the total pressure in the flask is 250 kPa and the mixture contains 0.110 mol of methanol.

Calculate the amount, in moles, of carbon monoxide present at equilibrium.

Calculate the partial pressure, in kPa, of carbon monoxide in this equilibrium mixture.

Give an expression for the equilibrium constant (K_p) for this reaction.

A different mixture of carbon monoxide and hydrogen is left to reach equilibrium at a temperature T.

Some data for this equilibrium are shown in Table 1.

Calculate the partial pressure, in kPa, of hydrogen in this equilibrium mixture.

Use the K_p value from Table 1 to calculate a value for K_p for the following reaction at temperature T.

Give the units for K_p

This question is about the equilibrium

State and explain the effect, if any, of a decrease in overall pressure on the

Calculate the partial pressure, in kPa, of SO₂ in this equilibrium mixture.

Table 4 shows the partial pressures of the gases at equilibrium.

Give an expression for the equilibrium constant (K_p) for this reaction.

Calculate the value of the equilibrium constant for this reaction and give its units.

What is the effect on the value of K_p if the pressure of this equilibrium mixture is increased at a constant temperature?

Tick (✓) one box.

What is the mole fraction of 1.0 g of a compound of relative molecular mass 100.0 dissolved in 30.0 g of a solvent of relative molecular mass 50.0?

Methanol can be manufactured in a reversible reaction as shown.

Figure 3 shows how the partial pressures change with time at a constant temperature.

Draw a cross (x) on the appropriate axis of Figure 3 when the mixture reaches equilibrium.

At equilibrium the mixture contains 0.120 mol of carbon monoxide.

Calculate the partial pressure, in kPa, of hydrogen in the equilibrium mixture.

Give an expression for the equilibrium constant (K_p) for this reaction.

State the units.

Some more carbon monoxide is added to the mixture in Question 06.2. The new mixture is allowed to reach equilibrium at temperature T.

State the effect, if any, on the partial pressure of methanol and on the value of K_p

Effect on partial pressure of methanol

State the effect, if any, of the addition of a catalyst on the value of K_p for this equilibrium. Explain your answer.

Sulfur trioxide decomposes on heating to form an equilibrium mixture containing sulfur dioxide and oxygen.

A sample of sulfur trioxide was heated and allowed to reach equilibrium at a given temperature. The equilibrium mixture contained 6.08 g of sulfur dioxide.

Calculate the mass, in g, of oxygen gas in the equilibrium mixture.

A different mass of sulfur trioxide was heated and allowed to reach equilibrium at 1050 K

The amounts of each substance in the equilibrium mixture are shown in Table 4.

For this reaction at 1050 K the equilibrium constant, K_p = 7.62 x 10⁵ Pa

Calculate the mole fraction of each substance at equilibrium. Give the expression for the equilibrium constant, K_p Calculate the total pressure, in Pa, of this equilibrium mixture.

K_p

For this reaction at 1050 K the equilibrium constant, K_p = 7.62 x 10⁵ Pa For this reaction at 500 K the equilibrium constant, K_p = 3.94 x 10⁴ Pa

Explain how this information can be used to deduce that the forward reaction is endothermic.

Use data from Question 07.3 to calculate the value of K_p, at 500 K, for the equilibrium represented by this equation.

The equation for the reaction between sulfur dioxide and oxygen is shown.

In an experiment, 2.00 mol of sulfur dioxide are mixed with 2.00 mol of oxygen. The total amount of the three gases at equilibrium is 3.40 mol

What is the mole fraction of sulfur trioxide in the equilibrium mixture?

Nitrogen reacts with hydrogen in this exothermic reaction

Which change increases the equilibrium yield of ammonia but has no effect on the value of the equilibrium constant K_p?

Nitrogen and hydrogen were mixed in a 1:3 mole ratio and left to reach equilibrium in a flask at a temperature of 550 K. The equation for the reaction between nitrogen and hydrogen is shown.

When equilibrium was reached, the total pressure in the flask was 150 kPa and the mole fraction of NH₃(g) in the mixture was 0.80

Calculate the partial pressure of each gas in this equilibrium mixture.

Give an expression for the equilibrium constant (K_p) for this reaction.

In a different equilibrium mixture, under different conditions, the partial pressures of the gases are shown in Table 2.

Calculate the value of the equilibrium constant (K_p) for this reaction and give its units.

The enthalpy change for the reaction is –92 kJ mol^–1

State the effect, if any, of an increase in temperature on the value of K_p for this reaction. Justify your answer.