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10 (a) Some acids are used in tests for ions - Edexcel - GCSE Chemistry - Question 10 - 2022 - Paper 1
Question 10
10 (a) Some acids are used in tests for ions. A bottle of one acid is shown in Figure 17. (i) The acid in Figure 17 can be used in the test for carbonate ions. Ex... show full transcript
Worked Solution & Example Answer:10 (a) Some acids are used in tests for ions - Edexcel - GCSE Chemistry - Question 10 - 2022 - Paper 1
Step 1
The acid in Figure 17 can be used in the test for carbonate ions. Explain, giving the name of the hazard symbol shown, what safety precautions should be taken when using this acid.
Answer
The acid in Figure 17 is nitric acid (HNO₃), which is classified under the hazard symbol of a corrosive substance. Safety precautions include wearing appropriate personal protective equipment such as gloves and goggles to prevent skin and eye contact, and working in a well-ventilated area or under a fume hood to avoid inhaling harmful fumes.
Step 2
Step 3
State a property of glass that makes it a suitable material to make the container for an acid.
Answer
A key property of glass that makes it suitable for containing acids is that it is chemically resistant. Glass does not react with most acids and can therefore safely hold acidic substances without degrading.
Step 4
Explain an improvement that needs to be made to step 3 to enable a bright flame colour to be produced.
Answer
An improvement to step 3 would be to ensure that the flame test wire is heated to red-hot before introducing it to the flame. This ensures that the metal ions are more likely to be excited and produce a brighter flame color.
Step 5
Step 6
Calculate the mass of hydrogen chloride in the acid used to test 20 samples.
Answer
To calculate the mass of hydrogen chloride in the acid used: Given that 1.00 dm³ of dilute hydrochloric acid contains 2199 g of hydrogen chloride, we need to determine the volume used for 20 samples. If each sample uses 5.00 cm³:
Total volume for 20 samples = 20 samples × 5.00 cm³/sample = 100.00 cm³ = 0.100 dm³.
Now, we find the mass in that volume:
a mass of HCl in 0.100 dm³ is: