1 (a) When a small amount of solid ammonium chloride is shaken with water, a colourless solution forms - Edexcel - GCSE Chemistry - Question 1 - 2012 - Paper 1
Question 1
1 (a) When a small amount of solid ammonium chloride is shaken with water, a colourless solution forms.
(i) What type of change has occurred?
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Worked Solution & Example Answer:1 (a) When a small amount of solid ammonium chloride is shaken with water, a colourless solution forms - Edexcel - GCSE Chemistry - Question 1 - 2012 - Paper 1
Step 1
What type of change has occurred?
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Answer
The change that has occurred is dissolving. This is indicated as the solid ammonium chloride mixes with water to form a solution.
Step 2
Describe how you could measure this change in temperature.
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Answer
To measure the change in temperature during the dissolving process:
Use a thermometer to measure the temperature of the water before adding the ammonium chloride.
After adding the solid, take the temperature again once the solid has completely dissolved.
The difference between the two temperatures indicates the change.
Step 3
Give the name of the type of chemical reaction that causes a decrease in temperature.
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Answer
The type of chemical reaction that causes a decrease in temperature is called endothermic.
Step 4
Give the name of the product that causes the mixture to fizz.
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Answer
The product that causes the mixture to fizz is carbon dioxide.
Step 5
State the difference you would see when the marble chips react with warm, instead of cold, acid.
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Answer
When marble chips react with warm acid, you would observe faster fizzing or that the reaction occurs more vigorously compared to cold acid.
Step 6
Explain what must be done to the marble chips so that the reaction with the warm, dilute hydrochloric acid is even faster.
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Answer
To increase the reaction rate when marble chips are added to warm, dilute hydrochloric acid, you can:
Break them up into smaller pieces to increase surface area.
Ensure a larger surface area by using powder instead of whole chips.
