JAMB Chemistry Past Questions & Answers - Page 62

The method used to extract a metal from its ore depends upon the stability of its compound in the ore, which in turn depends upon the reactivity of the metal:

  • The oxides of very reactive metals, such as aluminum, form stable oxides and other compounds. A lot of energy is needed to reduce them to extract the metal.

  • The oxides of lesser reactive metals, such as iron, form less stable oxides and other compounds. Relatively little energy is needed to reduce them to extract the metal.

  So, the method of extraction of a metal from its ore depends on the metal's position in the reactivity series.

Recall from pH formula pH = -Log [H+]

  H2SO4 → 2H+ + SO42-

  2H+ → 2 X0.05 = 0.1

  pH= -Log [0.1] = 1

M = \(\frac{MmIT}{96500n}\)

  Where

  M=mass

  Mm = Molar mass = 64g/mol

  I = current = 1.6A

  T= Time  =1h r=3600s

  N= No of Charge = +2

  M = \(\frac{64x \times 1.6 \times 3600}{96500 \times 2}\)

  M=1.91g

Increasing temperature in exothermic reaction favors the left/reactant side and decreasing temperature will favor the right/product side.

Diamond is a covalent macromolecule, and typical of a covalent substance is an insulator. All valence electrons are localized in well-defined covalent bonds and hence are not free to move through the structure