Unit 2 Topic 1 ✓ Flashcards
Physical Chemistry: Equilibrium
What is the System and Surroundings of a chemical reaction?
The system is the chemical reaction and the surroundings is everything else
What is an Open system?
An open system is a system where both matter and energy can move between the system and surroundings
What is a Closed system?
A closed system is a system where matter cannot move between the system and surroundings, but energy can
What is an Isolated system?
An isolated system is a system where neither matter nor energy can move between the system and surroundings
What is Stoichiometry?
Stoichiometry is the number of moles
What is an Equilibrium?
Equilibrium is the point at which the forward and reverse reactions reach the same rate
What happens to the concentrations of reactants and products at Equilibrium?
The concentrations of reactants and products in the system remain constant at equilibrium
(But not necessarily equal!)
What is Le Chatliers principle?
Le chatlier’s principle states that if a dynamic equilibrium is disturbed by a change in the conditions, the position of the equilibrium will shift to counteract the change
When does Pressure effect the equilibrium of a reaction?
Pressure effects the equilibrium if a reaction when:
- The reaction involves gases
- The number of moles of reactant is different from the number of moles of product
What is a Catalyst?
A catalyst is a chemical substance that doesn’t affect the position of an equilbrium, but decreases the time taken to reach equilibrium
What is a Homogenous equilibrium?
REMEMBER: Homo means the same
A homogenous equilibrium is when all substances in the reaction are present in the same phase
e.g. All are gases or all are in solution
What is a Heterogenous equilibrium?
REMEMBER: Hetero means different
A heterogenous equilibrium is when all substances in a reaction are present in more than one phase
e.g. Some solids and some gases
What is the Equilibrium constant? (K)
The equilibrium constant (K) is an expression that characterises the equilibrium composition of the reaction mixture.
It is depedent on temperature.
NOTE: The value of K is based on the conc of reactants/products
