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10 (a) A sample of potassium carbonate is contaminated with a small amount of sodium carbonate - Edexcel - GCSE Chemistry - Question 10 - 2019 - Paper 1
Question 10
10 (a) A sample of potassium carbonate is contaminated with a small amount of sodium carbonate. When a flame test is carried out on the sample, a bright yellow flame... show full transcript
Worked Solution & Example Answer:10 (a) A sample of potassium carbonate is contaminated with a small amount of sodium carbonate - Edexcel - GCSE Chemistry - Question 10 - 2019 - Paper 1
Step 1
Describe how you could show that potassium and sodium ions are present in this sample.
Answer
To demonstrate the presence of potassium and sodium ions in the sample, you would perform the following steps:
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Conduct a Flame Test: Take a small amount of the sample and introduce it to a flame. Observe the color of the flame.
- Result Interpretation: A bright yellow flame indicates the presence of sodium ions.
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Confirm Potassium Ion Presence: To confirm the presence of potassium ions, you can utilize a flame photometer.
- Using Flame Photometry: Measure the emission spectrum and check for specific wavelengths corresponding to potassium.
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Comparative Emission: You can compare the results to a reference sample known to contain potassium ions to validate the presence further.
Step 2
Write the ionic equation for this reaction.
Answer
The balanced ionic equation for the reaction between hydrochloric acid and sodium carbonate can be represented as follows:
ightarrow H_2O(l) + CO_2(g) $$ ### Breakdown of Components: - **Reactants**: - 2 moles of hydrogen ions from hydrochloric acid, \( HCl \) - 1 carbonate ion from sodium carbonate, \( Na_2CO_3 \) - **Products**: - Water, \( H_2O \) - Carbon dioxide gas, \( CO_2 \) This representation captures the key ionic species involved in the reaction.