AQA GCSE Chemistry Paper 2 150+ Questions & Answers (CHEM402) 2026 – Reaction Rates, Equilibrium, Organic Chemistry

AQA GCSE Chemistry Paper 2
||Latest Updates|| Graded A+
2026


How do you measure the rate of a reaction? - 🧠 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? - 🧠 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? - 🧠 ANSWER ✔✔Mean rate of

reaction = quantity of product formed/time taken


What units can you measure the rate of a reaction in? - 🧠 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 used or the quantity of product formed? - 🧠

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? - 🧠

ANSWER ✔✔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? - 🧠 ANSWER ✔✔Collision theory


What is collision theory? - 🧠 ANSWER ✔✔Chemical reactions can occur

only when reacting particles collide with each other and with sufficient

energy

,What is the activation energy of a reaction? - 🧠 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 rate of the reaction? - 🧠 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 the reaction? - 🧠 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 increase the rate of the reaction? - 🧠 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? - 🧠 ANSWER ✔✔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? - 🧠 ANSWER

✔✔Grind it into a powder that has smaller particle size




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3

, What effect does increasing the temperature of a reaction by 10°C have on

the rate of a reaction? - 🧠 ANSWER ✔✔It doubles it


What is a catalyst? - 🧠 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? - 🧠 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? - 🧠 ANSWER ✔✔It is not included in the chemical equation for the

reaction


What is a reversible reaction? - 🧠 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? - 🧠 ANSWER ✔✔


How can you change the direction of a reversible reaction? - 🧠 ANSWER

✔✔By changing the conditions; for example heating or cooling the reaction