Explore Rates of Reaction – GCSE Chemistry Revision

Chemistry Quiz - Rates of Reaction 1 (Questions)

Rates of reaction explains how fast chemicals change. Explore collisions, activation energy and catalysts, and learn how temperature, concentration, surface area and pressure affect reaction speed.

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Fascinating Fact:

Increasing temperature usually increases reaction rate because particles move faster and collide more energetically. More collisions then have enough energy to react.

In GCSE Chemistry, reaction rate is measured by how quickly reactants are used up or products are formed. Collision theory explains that particles must collide with enough energy and the correct orientation. You can speed reactions up by raising temperature, increasing concentration (or pressure for gases), using smaller pieces to increase surface area, or adding a catalyst to lower activation energy.

Key Terms

Rate of reaction: How fast reactants change into products, often measured by change in amount per unit time.
Activation energy: The minimum energy particles need for a successful collision that leads to a reaction.
Catalyst: A substance that increases reaction rate without being used up, usually by providing a lower-energy pathway.

Frequently Asked Questions

What factors affect the rate of reaction in GCSE Chemistry?

The main factors are temperature, concentration, surface area, pressure (for gases) and catalysts. Each one changes how often particles collide and how many collisions are successful.

Why does increasing surface area increase reaction rate?

Smaller pieces expose more surface for particles to hit. This increases collision frequency, so reactants are more likely to collide and form products each second.

How does a catalyst speed up a reaction?

A catalyst provides an alternative reaction pathway with lower activation energy. This means a greater proportion of collisions have enough energy to react at the same temperature.

Try These Related Quizzes

Which of the following methods is NOT a valid way to measure the rate of a chemical reaction?

[ ]	Measuring the mass of a reaction mixture
[ ]	Measuring the volume of gas given off
[ ]	Measuring the light transmitted through a solution
[ ]	Measuring the volume of liquid at the start of the reaction

Which piece of laboratory equipment would be useful for measuring the volume of gas given off?

[ ]	Beaker
[ ]	Gas syringe
[ ]	Conical flask
[ ]	Burette

Which of the following is NOT a factor that affects the rate of a chemical reaction?

[ ]	Temperature
[ ]	Concentration
[ ]	Surface area
[ ]	The speed at which the chemicals are mixed

Chemical reactions can only occur when...

[ ]	particles come together with sufficient energy
[ ]	particles come together for a sufficient amount of time
[ ]	particles mix together
[ ]	particles are able to separate

A catalyst is...

[ ]	a substance that slows down a chemical reaction, and is used up in the reaction
[ ]	a substance that speeds up a chemical reaction, and is used up in the reaction
[ ]	a substance that speeds up a chemical reaction, but is not used up in the reaction
[ ]	a substance that slows down a chemical reaction, but is not used up in the reaction

The smallest amount of energy required by particles to react is called...

[ ]	chemical energy
[ ]	reaction energy
[ ]	enabling energy
[ ]	activation energy

In order to accelerate the rate of a chemical reaction, there are two things which we can do. Pick the correct combination.

[ ]	Decrease the chances of particle collision Increase the energy the particles collide with
[ ]	Increase the chances of particle collision Increase the energy the particles collide with
[ ]	Increase the chances of particle collision Decrease the energy the particles collide with
[ ]	Decrease the chances of particle collision Decrease the energy the particles collide with

One method of increasing the chances of particles colliding during a reaction between gases is to...

[ ]	increase pressure
[ ]	decrease temperature
[ ]	use a catalyst
[ ]	decrease concentration

One method of increasing the energy the particles react with is to...

[ ]	increase pressure
[ ]	increase temperature
[ ]	use a catalyst
[ ]	decrease concentration

10.

If 80 cm³ of gas was given off in a reaction in 20 seconds, what was the average rate of reaction?

[ ]	4 cm/s
[ ]	4 cm³/s
[ ]	1,600 cm³/s
[ ]	0.25 cm³/s

Chemistry Quiz - Rates of Reaction 1 (Answers)

Which of the following methods is NOT a valid way to measure the rate of a chemical reaction?

[ ]	Measuring the mass of a reaction mixture
[ ]	Measuring the volume of gas given off
[ ]	Measuring the light transmitted through a solution
[x]	Measuring the volume of liquid at the start of the reaction

If you just measured the volume of a liquid at the start, it tells you nothing about how fast the reaction happened after that point in time. Any method of measuring the rate of reaction MUST be measurable during the whole time of the reaction

Which piece of laboratory equipment would be useful for measuring the volume of gas given off?

[ ]	Beaker
[x]	Gas syringe
[ ]	Conical flask
[ ]	Burette

This would be the most convenient and accurate method of measuring the volume of gas given off, although theoretically you could use any of the other pieces of equipment

Which of the following is NOT a factor that affects the rate of a chemical reaction?

[ ]	Temperature
[ ]	Concentration
[ ]	Surface area
[x]	The speed at which the chemicals are mixed

For a slow reaction, even if the chemicals are mixed instantaneously, it will still be a slow reaction and vice-versa

Chemical reactions can only occur when...

[x]	particles come together with sufficient energy
[ ]	particles come together for a sufficient amount of time
[ ]	particles mix together
[ ]	particles are able to separate

The amount of energy required is called the activation energy

A catalyst is...

[ ]	a substance that slows down a chemical reaction, and is used up in the reaction
[ ]	a substance that speeds up a chemical reaction, and is used up in the reaction
[x]	a substance that speeds up a chemical reaction, but is not used up in the reaction
[ ]	a substance that slows down a chemical reaction, but is not used up in the reaction

Make sure that you know this definition off by heart for your GCSE

The smallest amount of energy required by particles to react is called...

[ ]	chemical energy
[ ]	reaction energy
[ ]	enabling energy
[x]	activation energy

If particles collide with less than the activation energy, a reaction will not take place

In order to accelerate the rate of a chemical reaction, there are two things which we can do. Pick the correct combination.

[ ]	Decrease the chances of particle collision Increase the energy the particles collide with
[x]	Increase the chances of particle collision Increase the energy the particles collide with
[ ]	Increase the chances of particle collision Decrease the energy the particles collide with
[ ]	Decrease the chances of particle collision Decrease the energy the particles collide with

Particles will only react if they collide with each other so increasing the chances of collisions will increase the chances of a reaction occuring. Increasing the energy of collisions gives a better chance that they will collide with an energy greater than the activation energy

One method of increasing the chances of particles colliding during a reaction between gases is to...

[x]	increase pressure
[ ]	decrease temperature
[ ]	use a catalyst
[ ]	decrease concentration

Increasing pressure needs the gas mixture to be compressed. If it is compressed, the particles will be closer together and therefore more likely to collide