Required Practical: Investigating Temperature Changes (AQA GCSE Chemistry: Combined Science)

Objective

To perform a calorimetry study of the reaction between HCl and NaOH

Hypothesis

The temperature change will vary depending on the amounts of solutions involved

Materials

• Dilute hydrochloric acid
• Dilute sodium hydroxide solution
• Styrofoam (polystyrene) calorimeter & lid
• 25 cm³ measuring cylinder
• Thermometer & stirrer

Calorimetry apparatus

Diagram showing the apparatus for the calorimetry investigation for displacement, dissolving and neutralisation

Method

1. Using a measuring cylinder, place 25 cm³ of the NaOH solution into the calorimeter
2. Measure and record the temperature of the solution
3. Add 5 cm³ of the dilute HCl and stir
4. Measure and record the highest temperature reached by the mixture
5. Repeat steps 1 – 4 increasing the amount of acid added by 5 cm³ each time

Results

Record your results in a suitable table, eg:

Volume of acid (cm3)	Temperature (°C)
5	18
10	19

Evaluation

Plot a graph of the results and draw a line of best fit, using the graph to determine what volume of acid causes the biggest change in temperature

Conclusion

The larger the difference in the temperature the more energy is absorbed or released