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
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: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 type of change that has occurred when solid ammonium chloride is shaken with water is known as dissolving. This is because the solid dissolves in water to form a solution.
Step 2
Describe how you could measure this change in temperature.
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Answer
To measure the decrease in temperature, you would use a thermometer. First, take the temperature of the water before adding the ammonium chloride. Then, after adding the solid and allowing it to dissolve completely, take the temperature again. The difference in temperature readings will indicate the decrease in temperature.
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 an endothermic reaction.
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 hydrochloric acid, the reaction would occur faster, resulting in faster fizzing and more noticeable fizzing compared to the reaction with 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 make the reaction with warm dilute hydrochloric acid even faster, the marble chips should be broken up into smaller pieces. This increases the surface area available for the reaction, leading to a quicker reaction rate.
