Topic 11. Chemistry A level Edexcel questions
and answers
Describe a dynamic equilibrium - Dynamic equilibrium
- Rate of forward reaction = rate of reverse reaction
- Concentrations of all reactants and products remain constant.
- The system is closed, and on the large scale (macroscopic) everything is constant.
What happens if the conditions of an equilibrium reaction change? - - equilibrium
will move so that it can be re-established ( Le Chatliers Principle)
Define Homogenous equilibrium. - - all the chemicals (reactants and products) are
in the same phase
Define Heterogenous equilibrium. - - different states of matter are present in the
equilibrium.
What is the equilibrium constant Kc? - - product of product concentration to
reactant concentration.
, Topic 11. Chemistry A level Edexcel questions
and answers
Why aren't solids or pure liquids included in the value of Kc in a heterogenous
equilibrium? - - because their concentrations relatively remain the same
throughout the reaction
How to calculate units for Kc? - - replace the terms in the Kc expression with their
units
- cancel
What is affected by Kc? - TEMPERATURE
What is NOT affected by Kc? - - change in pressure
-change in conc of reactants or products
- adding a catalyst.
What two ways can you use to determine the concentration of reactants or
products at equilibrium? - 1. Titration
2. Colourimeter
and answers
Describe a dynamic equilibrium - Dynamic equilibrium
- Rate of forward reaction = rate of reverse reaction
- Concentrations of all reactants and products remain constant.
- The system is closed, and on the large scale (macroscopic) everything is constant.
What happens if the conditions of an equilibrium reaction change? - - equilibrium
will move so that it can be re-established ( Le Chatliers Principle)
Define Homogenous equilibrium. - - all the chemicals (reactants and products) are
in the same phase
Define Heterogenous equilibrium. - - different states of matter are present in the
equilibrium.
What is the equilibrium constant Kc? - - product of product concentration to
reactant concentration.
, Topic 11. Chemistry A level Edexcel questions
and answers
Why aren't solids or pure liquids included in the value of Kc in a heterogenous
equilibrium? - - because their concentrations relatively remain the same
throughout the reaction
How to calculate units for Kc? - - replace the terms in the Kc expression with their
units
- cancel
What is affected by Kc? - TEMPERATURE
What is NOT affected by Kc? - - change in pressure
-change in conc of reactants or products
- adding a catalyst.
What two ways can you use to determine the concentration of reactants or
products at equilibrium? - 1. Titration
2. Colourimeter
