In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate - AQA - GCSE Chemistry - Question 2 - 2016 - Paper 3
Question 2
In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.
A student has to check if ... show full transcript
Worked Solution & Example Answer:In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate - AQA - GCSE Chemistry - Question 2 - 2016 - Paper 3
Step 1
Description of the method using the burette
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Answer
The student should fill the burette with sodium hydroxide solution. It is essential to ensure there are no air bubbles in the burette and to record the initial volume of the sodium hydroxide solution.
Step 2
Using the pipette to measure hydrochloric acid
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Next, using a pipette, the student should measure a fixed volume of hydrochloric acid A and transfer it into the conical flask. It is important to use a white tile beneath the flask to observe the color change more easily.
Step 3
Adding indicator and conducting the titration
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An appropriate indicator, such as phenolphthalein, should be added to the hydrochloric acid in the conical flask. The student can then slowly add sodium hydroxide from the burette to the conical flask while continuously swirling the flask until a permanent color change is observed.
Step 4
Recording the volume of sodium hydroxide used
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The volume of sodium hydroxide used from the burette should be recorded. This determines how much base was required to neutralize the acid.
Step 5
Repeating the titration with hydrochloric acid B
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The entire procedure should then be repeated using hydrochloric acid B instead of A to find out the volume of sodium hydroxide required for complete neutralization.
Step 6
Comparison of results
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Finally, the volumes of sodium hydroxide used for both hydrochloric acid A and B should be compared. If the volumes are the same, then both acids are of the same concentration.
