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Experimental techniques
5 Class 11 Chemistry questions with answers and explanations.
Printable worksheet with answer key
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Components of a mixture of liquids with different boiling points are separated by:
- 1 Sublimation
- 2 Filtration
- 3 Fractional distillation
- 4 Crystallisation
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Correct answer: Fractional distillation
Fractional distillation separates liquids by boiling point.
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In paper chromatography, substances separate because of differences in:
- 1 Their attraction to the paper and the solvent
- 2 Density
- 3 Colour only
- 4 Mass only
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Correct answer: Their attraction to the paper and the solvent
Components travel at different speeds depending on their affinity to the two phases.
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Pure solid compounds are purified from solutions by:
- 1 Distillation
- 2 Centrifuge only
- 3 Crystallisation
- 4 Evaporation to dryness only
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Correct answer: Crystallisation
Crystallisation gives pure crystals from a saturated solution.
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The Rf value in chromatography is the ratio of:
- 1 Solvent to substance
- 2 Distance moved by substance to distance moved by solvent
- 3 Temperature to time
- 4 Mass of substance to solvent
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Correct answer: Distance moved by substance to distance moved by solvent
Rf = distance of spot / distance of solvent front.
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Solvent extraction works because a solute is:
- 1 A gas
- 2 Always ionic
- 3 A catalyst
- 4 More soluble in one solvent than another
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Correct answer: More soluble in one solvent than another
The solute moves into the solvent in which it dissolves better.