Neutralisation is when a chemical reaction takes place between an acid and base to produce a neutral solution of a salt and water.

An exothermic reaction is a type of reaction in which energy is transferred from the reactants to the surroundings e.g. combustion.

A method describes how an experiment is carried out; it is a step-by-step procedure.

A line graph involves two continuous variables being plotted to show if a relationship exists between them. Any trends in the data are shown with the addition of a line of best fit.

A conclusion sums up what has been found out during an investigation. It always refers to both the independent and dependent variables.

Energy changes: neutralisation practical

Combined science

In the Rate of Reaction unit, pupils will build on their understanding of energy changes to learn about the factors that influence the rate of chemical reactions.

In the Fuels and Energetics unit, pupils learned about energy changes during chemical reactions, including exothermic and endothermic reactions.

Energy changes in reactions

Physical activity and equipment requiring safe use

To determine the temperature change during the reaction

To ensure the acid is at room temperature

In the neutralisation practical, why is it important to measure the initial temperature of the hydrochloric acid?

Energy is absorbed as bonds break in the acid and alkali

Energy is released as heat when bonds form between water molecules

What is the primary reason for the temperature increase during a neutralisation reaction?

The temperature change of the reaction mixture

What is the dependent variable in the neutralisation experiment?

Polystyrene changes colour to indicate the completion of the reaction

Polystyrene is an insulator that minimises heat loss to the surroundings

Polystyrene reacts with the acid to produce more accurate results

Why is it important to use a polystyrene cup when conducting the neutralisation experiment?

Measure the pH change before and after the reaction

Measure the temperature change of the reaction mixture before and after 

Observe the colour change of the indicator

How can you experimentally determine whether a neutralisation reaction is exothermic or endothermic?

Approximately 1, indicating a highly acidic solution

Approximately 14, indicating a highly alkaline solution

Approximately 7, indicating a neutral solution

If 25 cm³ of hydrochloric acid reacts with 25 cm³ of sodium hydroxide, what will be the final pH of the solution?

A reaction that absorbs energy from the surroundings

A reaction that neither releases nor absorbs energy

A reaction that releases energy to the surroundings

What is the pH range of acidic solutions?

What is the pH range of alkaline solutions?

Changes colour to show if a solution is acidic or alkaline

Reacts with acids and bases to produce gas

A reaction between an acid and an alkali to form water and a salt

Content guidance

Risk assessment required - equipment

Adult supervision required

This lesson will be removed by end of Summer Term 2025.

Energy changes: neutralisation practical

Lesson outcome

Content guidance

This lesson will be removed by end of Summer Term 2025.