AQA GCSE Chemistry Exam
How do you measure the rate of a reaction?
By measuring the quantity of a reactant used or the quantity of product formed over
time
What is the equation for calculating the mean rate of a reaction by measuring the
amount of reactant used?
Mean rate of reaction = quantity of reactant used/time taken
What is the equation for calculating the mean rate of a reaction by measuring the
amount of product formed?
Mean rate of reaction = quantity of product formed/time taken
What units can you measure the rate of a reaction in?
g/s or cm3/s or mol/s
How do you calculate the rate of a reaction at a specific time from graph of the
quantity of reactant used or the quantity of product formed?
By measuring the gradient of a tangent drawn at that specific time on the graph
,What are the five factors that can affect the rate of a reaction?
Concentration of reactants in solution, pressure of reacting gases, surface area of
solid reactants, temperature and the presence of a catalyst
What theory can we use to explain how various factors affect the rate of a
reaction?
Collision theory
What is collision theory?
Chemical reactions can occur only when reacting particles collide with each other
and with sufficient energy
What is the activation energy of a reaction?
The minimum amount of energy that particles must have to react
According to collision theory why does increasing concentration of reactant in
solution increase the rate of the reaction?
It increases the frequency of collisions and so increases the rate of reaction
,According to collision theory why does increasing the pressure of reacting gases
increase the rate of the reaction?
It increases the frequency of collisions and so increases the rate of reaction
According to collision theory why does increasing the surface area of solid
reactants in solution increase the rate of the reaction?
It increases the frequency of collisions and so increases the rate of reaction
According to collision theory why does increasing temperature increase the rate
of the reaction?
It increases the frequency of collisions and makes the collision more energetic and
so increases the rate of reaction
How do you increase the surface area of a solid reactant?
Grind it into a powder that has smaller particle size
What effect does increasing the temperature of a reaction by 10°C have on the
rate of a reaction?
It doubles it
, What is a catalyst?
A chemical that changes the rate of a chemical reaction but is not used up in the
reaction
How do catalysts increase the rate of a reaction?
By providing a different pathway for the reaction that has a lower activation energy
How do you know in a reaction that a chemical is used in a reaction is a catalyst?
It is not included in the chemical equation for the reaction
What is a reversible reaction?
Where the products of a chemical reaction can react to produce the original
reactants
What is the symbol used in reversible reaction equations that shows that the
reaction is reversible?
How do you measure the rate of a reaction?
By measuring the quantity of a reactant used or the quantity of product formed over
time
What is the equation for calculating the mean rate of a reaction by measuring the
amount of reactant used?
Mean rate of reaction = quantity of reactant used/time taken
What is the equation for calculating the mean rate of a reaction by measuring the
amount of product formed?
Mean rate of reaction = quantity of product formed/time taken
What units can you measure the rate of a reaction in?
g/s or cm3/s or mol/s
How do you calculate the rate of a reaction at a specific time from graph of the
quantity of reactant used or the quantity of product formed?
By measuring the gradient of a tangent drawn at that specific time on the graph
,What are the five factors that can affect the rate of a reaction?
Concentration of reactants in solution, pressure of reacting gases, surface area of
solid reactants, temperature and the presence of a catalyst
What theory can we use to explain how various factors affect the rate of a
reaction?
Collision theory
What is collision theory?
Chemical reactions can occur only when reacting particles collide with each other
and with sufficient energy
What is the activation energy of a reaction?
The minimum amount of energy that particles must have to react
According to collision theory why does increasing concentration of reactant in
solution increase the rate of the reaction?
It increases the frequency of collisions and so increases the rate of reaction
,According to collision theory why does increasing the pressure of reacting gases
increase the rate of the reaction?
It increases the frequency of collisions and so increases the rate of reaction
According to collision theory why does increasing the surface area of solid
reactants in solution increase the rate of the reaction?
It increases the frequency of collisions and so increases the rate of reaction
According to collision theory why does increasing temperature increase the rate
of the reaction?
It increases the frequency of collisions and makes the collision more energetic and
so increases the rate of reaction
How do you increase the surface area of a solid reactant?
Grind it into a powder that has smaller particle size
What effect does increasing the temperature of a reaction by 10°C have on the
rate of a reaction?
It doubles it
, What is a catalyst?
A chemical that changes the rate of a chemical reaction but is not used up in the
reaction
How do catalysts increase the rate of a reaction?
By providing a different pathway for the reaction that has a lower activation energy
How do you know in a reaction that a chemical is used in a reaction is a catalyst?
It is not included in the chemical equation for the reaction
What is a reversible reaction?
Where the products of a chemical reaction can react to produce the original
reactants
What is the symbol used in reversible reaction equations that shows that the
reaction is reversible?
