1 In Questions 1 and 2 you will determine the percentage purity of industrial grade calcium carbonate, CaCO₃, by two different methods - CIE - A-Level Chemistry - Question 1 - 2016 - Paper 1
Question 1
1 In Questions 1 and 2 you will determine the percentage purity of industrial grade calcium carbonate, CaCO₃, by two different methods.
In the first method you will... show full transcript
Worked Solution & Example Answer:1 In Questions 1 and 2 you will determine the percentage purity of industrial grade calcium carbonate, CaCO₃, by two different methods - CIE - A-Level Chemistry - Question 1 - 2016 - Paper 1
Step 1
Method: Fill the tub with water
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Answer
Fill the tub with water to a depth of about 5 cm.
Step 2
Method: Prepare the measuring cylinder
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Answer
Fill the 250 cm³ measuring cylinder completely with water. Hold a piece of paper towel firmly over the top, invert the measuring cylinder, and place it in the water in the tub.
Step 3
Method: Clamp the measuring cylinder
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Remove the paper towel and clamp the inverted measuring cylinder so the open end is in the water just above the base of the tub.
Step 4
Method: Pipette the acid
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Pipette 25.0 cm³ of FA 2 into the reaction flask labelled X.
Step 5
Method: Secure the bung
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Answer
Check that the bung fits tightly in the neck of flask X, clamp flask X, and place the end of the delivery tube into the neck of the measuring cylinder.
Step 6
Method: Weigh the calcium carbonate
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Answer
Weigh the container that has FA 1 and record the mass.
Step 7
Method: Add calcium carbonate
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Answer
Remove the bung from the neck of the flask. Tip FA 1 into the flask and replace the bung immediately.
Step 8
Method: Observe gas production
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Answer
Shake occasionally and note the gas that is formed in the flask.
Step 9
Method: Repeat the process
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Answer
Repeat the whole procedure and record the mass in the space on the answer sheet.
Step 10
Method: Measure the gas volume
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Answer
Measure the volume of gas collected in the measuring cylinder.
Step 11
Method: Save contents for later
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Answer
Keep the contents of flask X for use in Question 2.
