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A student investigated the effect of temperature on the rate of a reaction - AQA - GCSE Chemistry - Question 4 - 2016 - Paper 2
Question 4
A student investigated the effect of temperature on the rate of a reaction. Figure 4 shows an experiment. The student: - put sodium thiosulfate solution into a con... show full transcript
Worked Solution & Example Answer:A student investigated the effect of temperature on the rate of a reaction - AQA - GCSE Chemistry - Question 4 - 2016 - Paper 2
Step 1
Explain why the solution goes cloudy.
Answer
The solution turns cloudy because sulfur (S) is formed as a solid precipitate during the reaction. When sodium thiosulfate reacts with hydrochloric acid, the production of sulfur causes the solution to appear cloudy as the solid particles disperse throughout the liquid.
Step 2
Step 3
State the effect that increasing the temperature of the sodium thiosulfate solution has on the rate of the reaction. Explain this effect in terms of particles and collisions.
Answer
Increasing the temperature of the sodium thiosulfate solution increases the rate of the reaction. This occurs because when the temperature rises, the particles move faster, which leads to a higher frequency of collisions between the reactant particles. Moreover, more particles will have energy that is greater than or equal to the activation energy required for the reaction, resulting in more successful reactions.
Step 4
Suggest how the student should change the method to investigate the rate of reaction at 5 °C.
Answer
The student should cool the reaction mixture to 5 °C, using a refrigerator or a suitable method to decrease the temperature of the sodium thiosulfate and hydrochloric acid solutions before mixing them.