Separation and Purification Quiz
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5 questions, one answer each
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1. Which separation technique would be most suitable for separating a soluble salt from a solution?
- A. Crystallisation
- B. Filtration
- C. Simple distillation
- D. Fractional distillation
2. A student obtains a sample of salt that has a melting point of 798°C. The literature value for pure sodium chloride is 801°C. What does this suggest about the purity of the sample?
- A. The sample is pure; small differences are normal in practical experiments
- B. The sample is impure; the melting point is lower than expected
- C. The sample is pure; the melting point must be exactly 801°C
- D. The sample is impure; the melting point is higher than expected
3. Simple distillation is used to separate components with which of the following characteristics?
- A. Different solubilities in a suitable solvent
- B. Significantly different boiling points
- C. Different particle sizes
- D. The same state of matter but different melting points
4. A student has a mixture of sand and salt dissolved in water. Which sequence of separation techniques should be used to recover both the salt and the sand in pure form?
- A. Filtration, followed by crystallisation
- B. Crystallisation, followed by filtration
- C. Simple distillation, followed by filtration
- D. Fractional distillation, followed by crystallisation
5. Crude oil contains hydrocarbons with boiling points ranging from 20°C to over 350°C. Explain why fractional distillation, rather than simple distillation, is the most suitable industrial separation method for crude oil.
- A. Fractional distillation uses multiple solvents to dissolve different hydrocarbons
- B. Fractional distillation uses a fractionating column with a temperature gradient to separate components with a wider range of boiling points more effectively
- C. Fractional distillation can separate insoluble solids from liquid hydrocarbons
- D. Fractional distillation requires less energy than simple distillation