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 coni... 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.
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Answer
The solution becomes cloudy because sulfur precipitates out of the reaction mixture. As sulfur forms, it creates a suspension that scatters light, making the solution appear cloudy.
Step 2
Give two variables the student must control to make the investigation a fair test.
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Answer
Volume of sodium thiosulfate.
Concentration of hydrochloric acid.
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.
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Answer
Increasing the temperature of the sodium thiosulfate solution results in an increased rate of reaction. This occurs because particles move faster at higher temperatures, leading to a higher frequency of collisions between reactant particles. More particles possess energy that is greater than or equal to the activation energy, resulting in more effective collisions and a higher reaction rate.
Step 4
Suggest how the student should change the method to investigate the rate of reaction at 5 °C.
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Answer
The student should cool the solutions or refrigerate them to reach the desired temperature of 5 °C before conducting the experiment.
