AQA GCSE Chemistry Required Practical Exam-Style Flashcards: Temperature Change

Flashcards covering the key concepts and procedures of the temperature change practical in AQA GCSE Chemistry.

Aim of the temperature change practical

To investigate how the temperature changes when different reactants are mixed.

Example of a temperature change experiment

Reacting hydrochloric acid with sodium hydroxide solution and measuring the temperature rise.

Equipment needed for temperature change practical

Polystyrene cup, thermometer, measuring cylinder, lid or cotton wool, reactant solutions.

Step 1 in the practical

Measure 30–50 cm³ of the first reactant using a measuring cylinder and pour it into the polystyrene cup.

Step 2 in the practical

Measure the starting temperature of the solution with a thermometer.

Step 3 in the practical

Add a measured volume of the second reactant (e.g. sodium hydroxide).

Step 4 in the practical

Stir the mixture and record the highest (or lowest) temperature reached.

Improving accuracy in temperature change experiment

Repeat using different concentrations or volumes to see how the temperature change varies.

How to calculate the temperature change

∆T = final temperature – initial temperature.

Exothermic reaction

A reaction in which the temperature increases and energy is released to the surroundings.

Endothermic reaction

A reaction in which the temperature decreases and energy is taken in from the surroundings.

Reducing heat loss

Use an insulated cup, lid, and cotton wool to prevent heat loss to surroundings.

Reason for using a polystyrene cup

It’s a good thermal insulator, reducing heat transfer.

Reason for unexpected temperature change

Some heat is lost to the air or absorbed by the container.

Safety precautions for the experiment

Wear goggles, handle acids and alkalis carefully, and wash immediately if chemicals contact skin.

Metal displacement reaction observation

You would still measure a temperature change, as most displacement reactions are exothermic.

Independent variable in the experiment

The reactant used (or its concentration/volume).

Dependent variable in the experiment

The temperature change (∆T).

Control variables in the experiment

Volume of solutions, concentration, and insulation setup.

Importance of this practical

It shows energy transfer in chemical reactions and supports understanding of exothermic/endothermic processes.