Module 5: Physical Chemistry and Transition Elements

Question 1

What is heterogenous equilibrium and how will it affect a Kc expression?

Answer 1

An equilibrium which contains species that aren’t all in the same state, and as a result, only aqueous and gaseous species in the reaction are included in the Kc expression and solid and liquid species are omitted.

Question 2

What is homogenous equilibrium and how will it affect a Kc expression?

Answer 2

An equilibrium which contains species that are all in the same state, and as a result, all species in the reaction are included in the Kc expression.

Question 3

What is the mole fraction of a gas?

Answer 3

Proportion of moles of a particular gas out of all the moles of all the gases in the gas mixture.

Question 4

Define partial pressure.

Answer 4

The contribution that a gas makes to the total pressure of a gas mixture.

Question 5

What is the general expression for Kp ?

Answer 5

(products)/(reactants)
only includes gases

Question 6

What is the only change that can result in a change in the value of K and why?

Answer 6

Change in temperature. This because if the change in temperature favours the forward reaction, yield of products will increase, and since K = products/reactants, K must change as well. The opposite is also true.

However, changes in concentration or pressure means a is no longer in equilibrium, and K has changed. As a result the system readjusts to restore the original value of K.