AQA A-Level Chemistry: Equilibrium constant, Kp

What is the effect of temperature on Kp?

For an exo reaction: -Increasing temperature will move the position of equilibrium in the endothermic direction, hence it shifts to the left. -This means that the numerator has decreased by a certain number of moles and the denominator will have increased. -Hence a smaller number divided by a larger number results in a smaller Kp. The important thing to remember is temperature HAS an effect on Kp.

What is Dalton's Law of Partial Pressures?

In a mixture of gases, A, B and C, the total pressure is the sum of all the partial pressures, p(A), p(B) and p(C).

How do you calculate the partial pressure of A?

Mole fraction of A x the total pressure

What effect does changing pressure have on Kp?

None.

What is the effect of a catalyst have on Kp?

None.

What type of brackets do you use in a Kp expression?

Round

Where is the equilibrium constant, Kp deduced from?

The equation for a reversible reaction occurring in the gas phase.

What is Kp?

The equilibrium constant calculated from partial pressures for a system at constant temperature.

What is the mole fraction of A?

The number of moles of gas A in the mixture divided by the total number of moles of gas in the mixture.

What is partial pressure?

The pressure an individual gas exerts in a mixture of gases.

How do we represent the mole fraction of a?

Xₐ (subscript)

What is the formula for concentration (Kc)

n= c x v moles = concentration x volume

How do we represent partial pressure, for example partial pressure of A?

p(A) Use a little p. Or Pa (little a)