Passage I
Reduction by carbon process, thermite process, and reduction by heating alone are different ways of
converting a metal oxide to pure metal. Reactions 1–3 are examples of these processes using zinc oxide,
manganese dioxide, and mercuric oxide, respectively.
Reaction 1: ZnO + C → Zn + CO
Reaction 2: 3MnO 2 + 4Al → 3Mn + 2Al 2 O 3
Reaction 3: 2HgO 2Hg + O 2
In each case, the resulting sample is composed of the metal and another product, which is filtered out
to leave only the pure metal.
Figures 1– 3 below show how percent pure metal (% PM) varied as a function of time in each of the
reactions in the presence of a magnetic field and without a magnetic field.
% PM = × 100
Figure 1
