Question

2. A certain copper ore contains 3.76% of Cu2S by mass, and the remainder of the ore contains no copper. In a particular year, a single open-air smelt furnace heated 22000 tons of this ore. Compute the maximum mass of copper metal that could have been obtained by this process. (Clarification: The tons in this problem are English tons, with 1 ton = 2000 lb. You can answer in g, kg, or lb, but the computer does not understand tons as a unit for the answer.)

Answer 1

The amount of copper that could have been obtained is 508,400 kg

Step-by-step explanation:

In 100 g ore, the mass of Cu2S is 3.76 g ( that is what it means 3.76 % Cu2S by mass)

1 mol Cu2S has a mass of 159.16 g, then, 3.76 g Cu2S are equal to:

3.76 g * (1 mol / 159.16 g) = 0.02 mol.

For every single mol of Cu2S we have 2 mol of Cu, then in 3.76 g Cu2S (0.02 mol), we have 0.04 mol Cu or (0.04 mol * 63.55 g (that´s the atomic weight of Cu) / 1mol) 2.542 g Cu.

Then, in 100 g ore, we have 2.542 g Cu.

1 ton = 2000 lb = 909.1 kg

22000 tons = 909.1 kg * 22000 = 2 x 10⁷ kg

Then if in 0.1 kg we have 0.002542 kg Cu, in 2 x 10⁷ kg we will have:

2 x 10⁷ kg * 0.002542 kg Cu / 0.1 kg = 508,400 kg Cu.