1 In an experiment, powdered calcium hydroxide was added to dilute hydrochloric acid and the pH was measured - Edexcel - GCSE Chemistry Combined Science - Question 1 - 2023 - Paper 1
Question 1
1 In an experiment, powdered calcium hydroxide was added to dilute hydrochloric acid and the pH was measured.
The method used was
step 1 measure 200 cm³ dilute hy... show full transcript
Worked Solution & Example Answer:1 In an experiment, powdered calcium hydroxide was added to dilute hydrochloric acid and the pH was measured - Edexcel - GCSE Chemistry Combined Science - Question 1 - 2023 - Paper 1
Step 1
State what should be done after step 2 to make sure that any reaction is complete.
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Answer
After adding the powdered calcium hydroxide, the mixture should be stirred or shaken to ensure thorough mixing and that the reaction is complete.
Step 2
Complete the word equation for the reaction.
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Answer
calcium hydroxide + hydrochloric acid → calcium chloride + water
Step 3
Which row of the table shows the state symbols for powdered calcium hydroxide and dilute hydrochloric acid in the balanced chemical equation?
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Answer
Row B
Step 4
Using Figure 1, give the pH of the acid at the start of the experiment.
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Answer
pH = 1
Step 5
Using Figure 1, give the mass of calcium hydroxide required to make a neutral mixture.
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mass of calcium hydroxide = 0.7 g
Step 6
Explain why the pH starts at a low value and ends at a higher value.
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The pH starts at a low value because the solution contains dilute hydrochloric acid, which is acidic. As calcium hydroxide is added, it neutralizes the acid, forming water and calcium chloride, causing the pH to rise until it reaches a neutral value.
