This question is about chemical analysis - AQA - GCSE Chemistry - Question 7 - 2015 - Paper 3
Question 7
This question is about chemical analysis.
A student has solutions of three compounds, X, Y and Z.
The student uses tests to identify the ions in the three compound... show full transcript
Worked Solution & Example Answer:This question is about chemical analysis - AQA - GCSE Chemistry - Question 7 - 2015 - Paper 3
Step 1
X ....................................................................
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Answer
The ions present in compound X are Fe²⁺ (iron(II)) and SO₄²⁻ (sulfate).
Step 2
Y ....................................................................
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Answer
The ions present in compound Y are Na⁺ (sodium) and I⁻ (iodide).
Step 3
Z ....................................................................
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Answer
The ions present in compound Z are Fe³⁺ (iron(III)) and Br⁻ (bromide).
Step 4
Compare the advantages and disadvantages of the two methods.
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Method 1
Advantages:
Weighing is accurate for determining mass.
Disadvantages:
Not all barium sulfate may be precipitated.
Precipitate may be lost during processing.
The precipitate needs to be completely dry for accurate measurements.
This method is time-consuming.
It requires additional energy for drying and filtering.
Method 2
Advantages:
More accurate as it works with standard concentrations.
Suitable for lower concentrations of barium hydroxide.
