Some students investigated the effect of temperature on the rate of reaction - AQA - GCSE Chemistry Combined Science - Question 2 - 2020 - Paper 2

To obtain accurate results, the students should implement the following steps:

1. Accurate Measurement: Use a measuring cylinder or a burette to measure exactly 50 cm³ of sodium thiosulfate solution and 10 cm³ of hydrochloric acid. This ensures that the volumes used in the reaction are precise.

2. Controlled Temperature: Before beginning the experiment, heat the sodium thiosulfate solution to a specific temperature using a water bath to maintain uniform heating. Record the temperature of the solution before mixing.

3. Consistent Setup: Place the conical flask with the solution over the black cross on a non-reflective surface to clearly observe the disappearance of the cross.

4. Timing: Start the timer immediately after adding hydrochloric acid to the sodium thiosulfate solution and ensure the timer is stopped precisely when the cross is no longer visible. Consider repeat trials for reliability.

5. After Reaction Monitoring: Conduct the experiment in a controlled environment to maintain stable room temperature and other conditions.

6. Data Recording: Record the temperature of the solution both before and after the reaction to ensure comparative analysis of the reaction rates at different temperatures.

By following these steps, the students can minimize experimental errors and improve the accuracy of their results.