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A student investigated the temperature change in displacement reactions between metals and copper sulfate solution - AQA - GCSE Chemistry - Question 5 - 2018 - Paper 1
Question 5
A student investigated the temperature change in displacement reactions between metals and copper sulfate solution. Table 2 shows the student's results. Table 2 M... show full transcript
Worked Solution & Example Answer:A student investigated the temperature change in displacement reactions between metals and copper sulfate solution - AQA - GCSE Chemistry - Question 5 - 2018 - Paper 1
Step 1
Plot the data from Table 2 on Figure 4 as a bar chart.
Answer
To plot the data, label the x-axis with the metals (Copper, Iron, Magnesium, Zinc) and the y-axis with the temperature increase in °C. Each metal should be represented by a bar with height according to their corresponding temperature increase:
- Copper: 0 °C
- Iron: 13 °C
- Magnesium: 43 °C
- Zinc: 17 °C
Ensure all axes are correctly labeled and the bars are plotted accurately.
Step 2
The student concluded that the reactions between the metals and copper sulfate solution are endothermic. Give one reason why this conclusion is not correct.
Answer
The conclusion is not correct because the temperature increases during the reactions, indicating that energy is released to the surroundings. This implies that the reactions are exothermic, as energy is being transferred out rather than absorbed.
Step 3
The temperature change depends on the reactivity of the metal. Describe a method to find the position of an unknown metal in this reactivity series.
Answer
To determine the reactivity of an unknown metal:
- Add the unknown metal to a fixed volume of copper sulfate solution.
- Measure the change in temperature after a predetermined time.
- Compare the temperature change of the unknown metal to the known values from Copper, Iron, Magnesium, and Zinc to classify it in order of reactivity.
- Ensure that all other conditions, such as concentration and mass of the metal, are kept constant to ensure valid results.
Step 4
Draw a fully labelled reaction profile for the reaction between zinc and copper sulfate solution on Figure 5.
Answer
The reaction profile should show the energy on the y-axis and the progress of reaction on the x-axis. It will start at a certain energy level, rise to a peak (activation energy), and then fall to a level lower than the starting point, representing the energy of the products. Label the activation energy line, the levels of reactants and products, and the overall energy change, indicating that the reaction is exothermic.