Chemistry · May / June 2024 · Paper 61 · Question 4
0620
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The question as text
A mixture contains three compounds: ● liquid ethanol ● solid sodium chloride ● solid zinc carbonate. Table 4.1 gives some information about these three compounds. Table 4.1 name of compound solubility in water solubility in ethanol ethanol soluble sodium chloride soluble insoluble zinc carbonate insoluble insoluble Describe how to obtain a pure sample of each of the three compounds, ethanol, sodium chloride and zinc carbonate, from the mixture. You are provided with common laboratory apparatus. [6]
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max 6
to obtain ethanol
MP1 filter the initial mixture (ethanol obtained as filtrate)
and then any five from:
to obtain zinc carbonate
MP2 add water to the residue / mixture
MP3 stir / warm after adding water
MP4 filter after adding water
MP5 wash residue from filtration after the addition of water
MP6 dry the solid zinc carbonate
to obtain sodium chloride
MP7 heat filtrate to remove water and obtain solid sodium chloride
If candidates do not have a valid method of obtaining ethanol then MP1 cannot be awarded and the maximum score is 5. If ethanol is obtained AFTER adding more ethanol to the mixture, then do not award MP1, maximum 5
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