● A state of equilibrium is reached in a closed system when the rates of the forward and reverse
reactions are equal.
Guidance
Physical and chemical systems should be covered.
● The equilibrium law describes how the equilibrium constant (Kc) can be determined for a particular chemical equation.
● The magnitude of the equilibrium constant indicates the extent of a reaction at equilibrium and is
temperature dependent.
● The reaction quotient (Q) measures the relative amount of products and reactants present during
a reaction at a particular point in time. Q is the equilibrium expression with non-equilibrium
concentrations. The position of the equilibrium changes with changes in concentration, pressure,
and temperature.
● A catalyst has no effect on the position of equilibrium or the equilibrium constant.

● The characteristics of chemical and physical systems in a state of equilibrium.
● Deduction of the equilibrium constant expression (Kc) from an equation for a homogeneous
reaction.
● Determination of the relationship between different equilibrium constants (Kc) for the same
reaction at the same temperature.
Guidance
Relationship between Kc values for reactions that are multiples or inverses of one another should be covered.
● Application of Le Chatelier’s principle to predict the qualitative effects of changes of temperature, pressure, and concentration on the position of equilibrium and on the value of the equilibrium constant.
Guidance
Specific details of any industrial process are not required.