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An experiment is carried out to measure the temperature change when solid ammonium chloride is dissolved in water - Edexcel - GCSE Chemistry - Question 5 - 2012 - Paper 1
Question 5
An experiment is carried out to measure the temperature change when solid ammonium chloride is dissolved in water. initial temperature of water = 19 °C final temper... show full transcript
Worked Solution & Example Answer:An experiment is carried out to measure the temperature change when solid ammonium chloride is dissolved in water - Edexcel - GCSE Chemistry - Question 5 - 2012 - Paper 1
Step 1
Explain what the temperature readings show about the type of heat change occurring when ammonium chloride dissolves in water.
Answer
The temperature readings indicate that the temperature of the solution decreases from 19 °C to 15 °C. This decrease suggests that the dissolution of ammonium chloride absorbs heat from the surrounding water, leading to a drop in temperature. This process is therefore endothermic, meaning that heat energy is taken in from the environment during the reaction.
Step 2
Use this information to complete the diagram.
Answer
To complete the diagram, draw a horizontal line for the reactants at a higher energy level. Then, place a downward slope showing the change in energy as the reaction progresses to the products, which should be at a lower energy level, indicating that heat energy is released. Label the reactants and products accordingly.