Module 3 - chapter 10 key terms Flashcards
Rate of chemical reaction
Measures how fast a reactant is being used up or how fast a product is being formed.
Collision theory
States that two particles must collide in order for a reaction to occur, only a small proportion of collisions will result in a chemical reaction.
adsorbed
When particles weakly bond onto the surface of something, e.g a catalyst.
Heterogenous catalyst
It has a different physical state to the reactants. Usually solids in contact with gaseous reactants or reactants in solution, the reactants are adsorbed onto the surface of a catalyst.
Homogenous catalysts
It has the same physical state as the reactants. It reacts with the reactants to form an intermediate, which then breaks down to give the product and regenerate the catalyst.
Reversible reactions
Reactions that take place in both the ‘forward’ and ‘reverse’ direction.
Dynamic equilibrium
The rate of the forwards reaction is equal to the rate of the reverse reaction.
The concentrations of the reactants and products does not change.
For a reaction to remain in equilibrium the system must be closed.
Closed system
Isolated from the surroundings, so the temperature, pressure and concentration of reactants and products are unaffected by outside influences.
Position of equilibrium
Indicates the extent of a reaction.
Le Chatelier’s principle
states that when a system in equilibrium is subjected to an external change the system readjusts itself to minimise the effect of that change.
Equilibrium constant
Provides the actual position of the equilibrium. The magnitude of an equilibrium constant indicates whether there are more reactants or more products in an equilibrium system.
Equilibrium law equation
aA + bB -> cC + dD
Kc = ([C]^c +[D]^d) ➗ ([A]^a + [B]^b)
Kc = 1
Position of equilibrium is halfway between the reactants and products
Kc > 1
Position of equilibrium that is towards the products
Kc < 1
Position of equilibrium that is towards the reactants.
