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. The ore was likely malachite (Cu2 (OH) 2CO3). What is the mass percent of copper in malachite?

57.5%

Explanation:

The mass percent of copper in malachite (Cu2 (OH) 2CO3) can be determined as follow:

Molar Mass of malachite (Cu2 (OH) 2CO3) = (2x63.5) + 2 (16 + 1) + 12 + (16x3) = 127 + 2 (17) + 12 + 48 = 127 + 34 + 12 + 48 = 221g/mol

Mass of Cu in Cu2 (OH) 2CO3 = 2 x 63.5 = 127g

The percentage by mass of Cu in Cu2 (OH) 2CO3 is given by:

Mass of Cu/Molar Mass of Cu2 (OH) 2CO3 x 100

=> 127/221 x 100

=> 57.5%

Therefore, 57.5% by mass of Cu is contained in malachite Cu2 (OH) 2CO3