Concept explainers
Copper metal can be prepared by roasting copper ore, which can contain cuprite (Cu2S) and copper(II) sulfide.
Cu2S(s) + O2(g) → 2 Cu(s) + SO2(g)
CuS(s) + O2(g) → Cu(s) + SO2(g)
Suppose an ore sample contains 11.0% impurity in addition to a mixture of CuS and Cu2S. Heating 100.0 g of the mixture produces 75.4 g of copper metal with a purity of 89.5%. What is the weight percent of CuS in the ore? The weight percent of Cu2S?
Interpretation:
The weight percentage of
Concept introduction:
- For chemical reaction balanced chemical reaction equation written in accordance with the Law of conservation of mass.
- Law of conservation of mass states that for a reaction total mass of the reactant and product must be equal.
- The molar mass of an element or compound is the mass in grams of 1 mole of that substance, and it is expressed in the unit of grams per mol (g/mol).
- Stoichiometric factor is a relationship between reactant and product which is obtained from the balanced chemical equation for a particular reaction.
- Weight percent of elements of a compound is the ratio of weight of element to the weight of whole compound and multiplied with hundred.
Answer to Problem 103GQ
The weight percentage of
Explanation of Solution
Balanced chemical equation for the reaction occurred in the preparation of copper from cuprite
Then the mass of
Mass of
Considering A as the mass of
Mass of
Similarly mass of
Mass of
Total mass of copper metal produced,
Thus,
But here total Cu metal produced with impurity =
Therefore mass of impurity is,
That is,
Calculated mass of
Substituting this in the above equation,
Then the value of B is
The weight percentage of
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