AQA GCSE CHEMISTRY PAPER 2
QUESTIONS WITH CRRECT ANSWERS 2025
How do you measure the rate of a reaction? - CORRECT ANSWER -
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? - CORRECT ANSWER -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? - CORRECT ANSWER -Mean rate of reaction = quantity of product formed/time taken
What units can you measure the rate of a reaction in? - CORRECT ANSWER -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 u
sed or the quantity of product formed? - CORRECT ANSWER -
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? - CORRECT ANSWER -
Concentration of reactants in solution, pressure of reacting gases, surface area of solid reactants, temp
erature and the presence of a catalyst
What theory can we use to explain how various factors affect the rate of a reaction? -
CORRECT ANSWER -Collision theory
What is collision theory? - CORRECT ANSWER -
Chemical reactions can occur only when reacting particles collide with each other and with sufficient e
nergy
What is the activation energy of a reaction? - CORRECT ANSWER -
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 rat
e of the reaction? - CORRECT ANSWER -
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 th
e reaction? - CORRECT ANSWER -
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 increas
e the rate of the reaction? - CORRECT ANSWER -
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? -
CORRECT ANSWER -
It increases the frequency of collisions and makes the collision more energetic and so increases the rat
e of reaction
How do you increase the surface area of a solid reactant? - CORRECT ANSWER -
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? -
CORRECT ANSWER -It doubles it
What is a catalyst? - CORRECT ANSWER -
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? - CORRECT ANSWER -
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? -
CORRECT ANSWER -It is not included in the chemical equation for the reaction
What is a reversible reaction? - CORRECT ANSWER -
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? -
CORRECT ANSWER -
How can you change the direction of a reversible reaction? - CORRECT ANSWER -
By changing the conditions; for example heating or cooling the reaction
Describe the energy changes in a reversible reaction - CORRECT ANSWER -
One direction will be exothermic and the other direction endothermic
When is equilibrium in a reversible reaction achieved in apparatus which prevents the escape of react
ants and products? - CORRECT ANSWER -
When the rate of the forward and reverse reactions occur at exactly the same rate
What affects the relative amount of all the reactants and products at equilibrium in a reversible reacti
on? - CORRECT ANSWER -The conditions
What happens to an equilibrium if any of the conditions change? - CORRECT ANSWER -
The system responds to counteract the change
What does Le Chatelier's principle predict? - CORRECT ANSWER -
The effects of changing conditions on a system at equilibrium
What affect will changing the concentration of one of the reactants in a reversible reaction have on th
e equilibrium? - CORRECT ANSWER -
The system will no longer be in equilibrium and the concentration of all the substances will change un
til equilibrium is reached again
What happens when the concentration of a reactant is increased in a reversible reaction? -
CORRECT ANSWER -More products will be formed until equilibrium is reached again
What happens when the concentration of a product is decreased in a reversible reaction? -
CORRECT ANSWER -More reactant will react until equilibrium is reached again
QUESTIONS WITH CRRECT ANSWERS 2025
How do you measure the rate of a reaction? - CORRECT ANSWER -
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? - CORRECT ANSWER -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? - CORRECT ANSWER -Mean rate of reaction = quantity of product formed/time taken
What units can you measure the rate of a reaction in? - CORRECT ANSWER -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 u
sed or the quantity of product formed? - CORRECT ANSWER -
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? - CORRECT ANSWER -
Concentration of reactants in solution, pressure of reacting gases, surface area of solid reactants, temp
erature and the presence of a catalyst
What theory can we use to explain how various factors affect the rate of a reaction? -
CORRECT ANSWER -Collision theory
What is collision theory? - CORRECT ANSWER -
Chemical reactions can occur only when reacting particles collide with each other and with sufficient e
nergy
What is the activation energy of a reaction? - CORRECT ANSWER -
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 rat
e of the reaction? - CORRECT ANSWER -
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 th
e reaction? - CORRECT ANSWER -
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 increas
e the rate of the reaction? - CORRECT ANSWER -
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? -
CORRECT ANSWER -
It increases the frequency of collisions and makes the collision more energetic and so increases the rat
e of reaction
How do you increase the surface area of a solid reactant? - CORRECT ANSWER -
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? -
CORRECT ANSWER -It doubles it
What is a catalyst? - CORRECT ANSWER -
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? - CORRECT ANSWER -
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? -
CORRECT ANSWER -It is not included in the chemical equation for the reaction
What is a reversible reaction? - CORRECT ANSWER -
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? -
CORRECT ANSWER -
How can you change the direction of a reversible reaction? - CORRECT ANSWER -
By changing the conditions; for example heating or cooling the reaction
Describe the energy changes in a reversible reaction - CORRECT ANSWER -
One direction will be exothermic and the other direction endothermic
When is equilibrium in a reversible reaction achieved in apparatus which prevents the escape of react
ants and products? - CORRECT ANSWER -
When the rate of the forward and reverse reactions occur at exactly the same rate
What affects the relative amount of all the reactants and products at equilibrium in a reversible reacti
on? - CORRECT ANSWER -The conditions
What happens to an equilibrium if any of the conditions change? - CORRECT ANSWER -
The system responds to counteract the change
What does Le Chatelier's principle predict? - CORRECT ANSWER -
The effects of changing conditions on a system at equilibrium
What affect will changing the concentration of one of the reactants in a reversible reaction have on th
e equilibrium? - CORRECT ANSWER -
The system will no longer be in equilibrium and the concentration of all the substances will change un
til equilibrium is reached again
What happens when the concentration of a reactant is increased in a reversible reaction? -
CORRECT ANSWER -More products will be formed until equilibrium is reached again
What happens when the concentration of a product is decreased in a reversible reaction? -
CORRECT ANSWER -More reactant will react until equilibrium is reached again
