FORM III TOPIC 8. EXTRACTION OF METALS:

                   

CHEMISTRY FORM THREE QUESTIONS AND ANSWERS 

QUESTIONS.

 1. Identify the most correct answer.
     i) The series of elements arranged in order of increase of electrode potential.
   A: periodic table  B: reactivity series
   C: groups.             D: period

ii) Ionize by electron loss.
   A: positive charge  B: metals  C: halogens      D: non-metals

(iii) Metals that found as oxides
       A: are of medium reactivity
       B: are very very reactive
       C: are least reactive
        D: lead and gold

 (iv) Obtaining metal from its ore

        A: it is mixture separation
        B: it is extraction of metal
        C: Concentration of metal ore
        D: purification of metal

 (v) It occurs as free element
       A: aluminium  B: lead  C: sodium  D: platinum

 (vi) Extracted from water soluble salt
        A: sodium chloride  potassium chloride
        C: sodium.           D: silver

 (vii) The Down's electrolytic cell is the apparatus for extracting:-
         A: sodium B: aluminium  C: platinum  D: iron

 (viii) Loss of electrons, oxygen or increase of oxidation number
          A: oxidation  B: properties of metals
          C: properties of non-metals  D:reduction

  (ix) Bauxite and cryolite are metal ores for
         A: aluminium  B: sodium  C: calcium  D: potassium

  (x) Bayer process is the process of extracting
        A: copper  B: aluminium  C: sulphur  D: potassium

2. Match list  A  and  list  B

          List  A

  i) Evaporating metals by heating leaving behind impurities.

 ii) Impurities escapes as oxides when impure metal exposed to the air.

 iii) Pure metal ore obtained.

 iv) Results to deposition of pure metal on the cathode after impure metal being dissolved in an electrolyte.

 v) Ore is heated in presence of air below its melting point.

 vi) Ore is heated in absence of air below its melting point.

 vii) Chemically, the metal ore is not decomposed when impurities are removed from it.

 viii) Crude metal.

  ix) Haematite

        List  B

  A: When metal ore concentrated

  B: Dressing of metal ore

  C: Impure metal

  D: Refining metal by electrolysis
  E: Metal destruction

  F: Modification of metals

  G: Distillation of metal

  H: Boiling of metals

  I:  Ore that iron extracted from.

  J: Ore that magnesium extracted

  K: Calcination

  L: Roasting

  M: Refining by electrolysis

  N: Refining by oxidation

3.  Explain at least three physical and four chemical properties of metals.

4. Sodium, magnesium, zinc, copper and silver are arranged in order of reactivity series, in which sodium being the most reactive metal.

(a) Which one of these metals is:-

     (i) likely to tarnish most rapidly when it is exposed to the air?

   (ii) most likely to be found in nature?

   (iii) least likely to react with steam?

  (b) Name two metals that extracted by electrolysis of their molten chlorides and state reason for this method.

5. What is the meaning of the following terms and statements.
 
     i) Metal ores
    ii) Extraction of metals
   iii) Coke

6. With examples name and explain types of methods used in extraction of metals.

7. The following is a diagram which shows extraction of sodium

   (a) Name the diagram.
   (b) Name the ore used in extraction of sodium
   (c) label parts of diagrams indicated by letters.
    (d) Name the compound used to lower the melting point of the ore mentioned in 7(b) above.

    (e) Explain, how sodium extracted by using apparatus named in 7(a) above.

8.(a) Explain the Bayer process extracting  aluminium.
   (b) Mention the uses of aluminium.

9. (a) List down the stages used in extraction of copper.
    (b) Mention importance of copper.

10. (a) Observe the diagram below which shows extraction of iron then answer the questions.

  

(a) Name the ore which used
(b)Which substances are fed into furnace at point A?
(c) Name the substance introduced at point C.
(d) Write the balanced chemical reaction taking place at
      i) 1600°C
     ii) 700°C
    iii) 250°C
(e) What is the function of Carbon monoxide formed in the blast furnace?
(f) Name the products formed at D and  E.
(g) Why CaCO3 is added in a blast furnace?

                       ANSWERS.
     i) B  ii)  B  iii) A.  iv) B  v) D  vi) C  vii) A   viii) A  ix) A  x) B

    i) G  ii) N  iii) A  iv)  D  v) L  vi)  K  vii)  B  viii)  C  ix) I

3. - Physical properties of metals.
    a) They are malleable
             Because they can be hammered into thin sheets