Copper was the first metal to be produced from its ore because it is the easiest to smelt, that is, to refine by heating in the presence of carbon (hence the early occurrence of the Bronze Age). The ore was likely malachite (Cu₂(OH)₂CO₃). What is the mass percent of copper in malachite? A)28.7% B)45.2% C)57.5% D)40.3% E)74.6%

Question

Quizplus · Accepted Answer

The formula of malachite is Cu2CO3(OH)2. The atomic mass of Cu is 63.55 g/mol and the molar mass of malachite is 221.1 g/mol. Therefore, the mass percent of copper in malachite is:

63.55 g/mol Cu × 2 mol Cu/mol malachite × 100% ÷ 221.1 g/mol malachite = 57.5%

Therefore, the best choice is C.

Copper Was the First Metal to Be Produced from Its