a) A student investigated the reaction between potassium iodide and lead nitrate - Edexcel - GCSE Chemistry - Question 3 - 2020 - Paper 1
Question 3
a) A student investigated the reaction between potassium iodide and lead nitrate.
(i) Solutions of potassium iodide and lead nitrate were mixed together.
Lead iodide... show full transcript
Worked Solution & Example Answer:a) A student investigated the reaction between potassium iodide and lead nitrate - Edexcel - GCSE Chemistry - Question 3 - 2020 - Paper 1
Step 1
Complete the word equation.
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Answer
The word equation can be completed as follows:
Potassium iodide + Lead nitrate → Lead iodide + Potassium nitrate
Step 2
State how the results in Figure 4 show that mass is conserved in this reaction.
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Answer
The results indicate that the total mass of reactants (21.7 g) is equal to the total mass of products (21.7 g). This demonstrates that mass is conserved during the reaction, as no mass is lost or gained.
Step 3
Name a piece of apparatus that should be used to measure the 100 cm³ of water in step 1.
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Answer
A measuring cylinder should be used to accurately measure 100 cm³ of water.
Step 4
State what the student must do before step 2 to be able to work out the temperature decrease.
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Answer
The student must measure the initial temperature of the water before adding the ammonium nitrate crystals.
Step 5
State why a polystyrene cup is used in this experiment.
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A polystyrene cup is used because it is an insulator, which reduces heat transfer between the solution and the surroundings, allowing for more accurate temperature readings.
Step 6
Use the words from the box to complete the labels on Figure 6.
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Answer
The labels in Figure 6 can be completed as follows:
The left side should be labeled reactants.
The peak of the curve should be labeled activation energy.
