JAMB and WAEC Chemistry questions: Separation of mixtures and purification

42 questions with answers and explanations. Tap an option to check yourself.

1. Question 1· Separation of mixtures and purification· JAMB

   Ethanol (boiling point 78 °C) can be separated from water by

   • Afractional distillation
   • Bfiltration
   • Cdecantation
   • Dcrystallisation

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   Explanation and discussion

2. Question 2· Separation of mixtures and purification· WAEC

   The liquid that passes through the filter paper during filtration is the

   • Afiltrate
   • Bresidue
   • Csolute
   • Dprecipitate

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   Explanation and discussion

3. Question 3· Separation of mixtures and purification· WAEC

   A mixture of ammonium chloride and sodium chloride is separated by

   • Aevaporation
   • Bfiltration
   • Csublimation
   • Ddecantation

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   Explanation and discussion

4. Question 4· Separation of mixtures and purification· WAEC

   A mixture of chalk and water is separated by

   • Afiltration
   • Bdistillation
   • Csublimation
   • Dchromatography

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   Explanation and discussion

5. Question 5· Separation of mixtures and purification· WAEC

   In paper chromatography of a black ink, the component that travels furthest up the paper is the one that is

   • Amost strongly held by the paper
   • Bleast soluble in the solvent
   • Cmost soluble in the solvent and least held by the paper
   • Ddarkest in colour

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   Explanation and discussion

6. Question 6· Separation of mixtures and purification· JAMB

   The purest sample of common salt is obtained from sea water by

   • Aevaporation to dryness
   • Bcrystallisation
   • Cfiltration only
   • Ddistillation of the salt

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   Explanation and discussion

7. Question 7· Separation of mixtures and purification· JAMB

   A pure solid can be identified by its

   • Asharp melting point
   • Bcolour
   • Chigh density
   • Dsolubility in water

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   Explanation and discussion

8. Question 8· Separation of mixtures and purification· WAEC

   The best method of obtaining crystals of copper(II) tetraoxosulphate(VI) from its solution is

   • Afiltration
   • Bdistillation
   • Ccrystallisation
   • Dsublimation

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   Explanation and discussion

9. Question 9· Separation of mixtures and purification· WAEC

   Ogogoro is obtained by distilling fermented palm wine. The separation depends on a difference in the components'

   • Asolubilities
   • Bdensities
   • Cboiling points
   • Dcolours

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   Explanation and discussion

10. Question 10· Separation of mixtures and purification· JAMB

    A mixture of iodine crystals and sand is best separated by

    • Adistillation
    • Bfiltration
    • Csublimation
    • Dchromatography

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    Explanation and discussion

11. Question 11· Separation of mixtures and purification· JAMB

    Which method is best for obtaining pure water from sea water?

    • Adecantation
    • Bfiltration
    • Cdistillation
    • Dsublimation

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    Explanation and discussion

12. Question 12· Separation of mixtures and purification· JAMB

    Blue copper(II) tetraoxosulphate(VI) crystals are obtained by crystallisation rather than by evaporating to dryness because

    • Aevaporation uses less heat
    • Bcrystallisation is faster
    • Cevaporating to dryness would drive off the water of crystallisation
    • Dcrystallisation removes all impurities

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    Explanation and discussion

13. Question 13· Separation of mixtures and purification· WAEC

    The method used to separate sand from water is

    • Afiltration
    • Bsublimation
    • Ccrystallisation
    • Ddistillation

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    Explanation and discussion

14. Question 14· Separation of mixtures and purification· JAMB

    Steam distillation is used to separate substances that are

    • Asolids that sublime
    • Bmiscible with water
    • Cimmiscible with water and decompose at their boiling points
    • Dgases at room temperature

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    Explanation and discussion

15. Question 15· Separation of mixtures and purification· JAMB

    A pure liquid can be identified by its

    • Asmell
    • Bcolour
    • Cconstant boiling point
    • Dvolume

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    Explanation and discussion

16. Question 16· Separation of mixtures and purification· WAEC

    Which method is best for separating the coloured components of ink?

    • AChromatography
    • BEvaporation
    • CFiltration
    • DDecantation

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    Explanation and discussion

17. Question 17· Separation of mixtures and purification· WAEC

    A separating funnel is used to separate

    • Atwo immiscible liquids such as oil and water
    • Bsalt from water
    • Csand from water
    • Dtwo miscible liquids

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    Explanation and discussion

18. Question 18· Separation of mixtures and purification· JAMB

    

    The apparatus shown is used to separate

    • Aa solid from a solution
    • Btwo immiscible liquids, such as kerosene and water
    • Ctwo miscible liquids
    • Dthe dyes in ink

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    Explanation and discussion

19. Question 19· Separation of mixtures and purification· JAMB

    The purity of a solid sample can be tested by finding its

    • Amass
    • Bcolour
    • Cmelting point
    • Dvolume

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    Explanation and discussion

20. Question 20· Separation of mixtures and purification· WAEC

    The purity of a solid can be tested by finding its

    • Acolour
    • Bmelting point
    • Cmass
    • Dshape

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    Explanation and discussion