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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 decreased from 19 °C to 15 °C when ammonium chloride dissolved in water. This signifies that heat energy was absorbed from the surroundings during the dissolution process. Therefore, the process is classified as endothermic, as it results in a cooling effect.
Step 2
Use this information to complete the diagram.
Answer
In the provided diagram, mark a horizontal line at the reactants level to show the energy level of the reactants before the reaction begins. Then, represent a drop in heat energy as the reaction progresses, indicating that heat is released, placing the product level below the reactants. Label this decrease to reflect it as an exothermic reaction.