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A student investigated the temperature change when zinc reacts with copper sulfate solution - AQA - GCSE Chemistry - Question 2 - 2015 - Paper 2
Question 2
A student investigated the temperature change when zinc reacts with copper sulfate solution. The student used a different concentration of copper sulfate solution f... show full transcript
Worked Solution & Example Answer:A student investigated the temperature change when zinc reacts with copper sulfate solution - AQA - GCSE Chemistry - Question 2 - 2015 - Paper 2
Step 1
Step 2
Suggest one improvement the student could make to the apparatus in Figure 3.
Answer
The student could use a plastic or polystyrene cup or add a lid to minimize heat loss. This improves the investigation as it helps to maintain the temperature throughout the reaction, allowing for more accurate readings.
Step 3
Describe and explain the trends shown in the student's results.
Answer
Description
The table shows that as the concentration of copper sulfate increases, the increase in temperature also increases, reaching a maximum increase of 35°C at 0.7 moles per dm³. This indicates a correlation between concentration and temperature change.
Explanation
Initially, the temperature change increases with the concentration due to a higher number of reactant molecules, which leads to more effective collisions and higher energy release during the reaction. However, after 0.7 moles per dm³, the temperature increase levels off, suggesting that once the copper sulfate concentration exceeds a certain point, there may be an excess of reactant, causing no further energy increase despite ongoing reactions.