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 (S) forms as a precipitate, making the liquid opaque. This indicates that the reaction is taking place and the solid sulfur is suspended in the liquid.
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 increases the rate of reaction. This happens because particles move faster at higher temperatures. As a result, the frequency of collisions between particles increases. Additionally, more particles will have energy equal to or greater than the activation energy, leading to a higher likelihood of successful collisions that result in reaction.
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 solution or decrease the temperature of the solutions to reach 5 °C before starting the experiment.
