Galena (an ore) is partially oxidized by passing air through it at high temperature. After some time, the passage of air is stopped, but the heating is continued in a closed furnance such that the con

Question

Galena (an ore) is partially oxidized by passing air through it at high temperature. After some time, the passage of air is stopped, but the heating is continued in a closed furnance such that the contents undergo selfreduction. The weight (in kg ) of Pb produced per kg of $O_{2}$ consumed is $____$ 。

(Atomic weights in g mol^-1 : O = 16, S = 32, Pb = 207)

TestHub · Accepted Answer

On partial oxidation, galena forms lead oxide:

$2 P b S + 3 O_{2} \to 2 P b O + 2 S O_{2}$

Then self-reduction occurs:

$P b S + 2 P b O \to 3 P b + S O_{2}$

From the overall process, $3 m o l O_{2} p ro d u ce 3 m o lP b$ .

So, 1 mol O₂ produces 1 mol Pb = 207 g Pb.

$P b p er k g O_{2} = \frac{207}{32} \times 1000 = 6.47 \approx 6.40 k g$

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