Chemistry Rates & Equilibrium Nov 2018 Flashcards
What equations are used to calculate the mean rate of reaction (mrr)?
mrr = quantity of reactant used / time
or
mrr = quantity of product formed / time
What 4 factors effect the rate of reaction?
Temperature, Concentration/pressure, Surface area (solid only) & catalyst
What happens when there is a higher temperature in a reaction?
Particles have more kinetic energy so they are moving faster, the frequency of successful reactions increases so more reactions occur with sufficient energy
What happens when there is a higher concentration/pressure in a reaction?
Particles are less spread out meaning that there are more particles in the same volume and the frequency of successful collisions increases
What happens when there is a higher surface area in a reaction?
More particles are exposed so the frequency of successful reactions increases
What happens when are more catalysts in a reaction?
The activation energy is reduced which brings down the amount of energy needed for successful collisions so the frequency of successful collisions increases
What is dynamic equilibrium?
when forward and backward reactions are taking place simultaneously and at the same rate
What is the symbol used to shoe that a reaction is reversible?
⇌ (replaces normal arrow)
What is a reversible reaction?
A reaction where the reactants form products which can then form back into the original reactants. (e.g. heat hydrated copper sulphate (making dehydrated copper sulphate), then add water to it and hydrated copper sulphate is made
What is a closed system?
Where a reaction takes place inside apparatus of which no substances can come in or out.
What does it mean if the equilibrium lies to the right or left? What is this called?
This is called the equilibrium yield or Le Châtelier’s Principle
Right - There are more products than reactants
Left - There are more reactants than products
What is activation energy?
The minimum amount of energy particles need to react
What is collision theory?
For a chemical reaction to take place, particles of the reactants must collide with enough energy to react (Activation Energy). The rate of reaction depends on the frequency of successful reactions.
