What is the percent composition of chalcopyrite,CuFeS₂?

Question

Quizplus · Accepted Answer

To find the percent composition, we need to find the molar mass of the compound and then divide the molar mass of each element by the total molar mass of the compound and multiply by 100%.

Molar mass of Cu = 63.55 g/mol 
Molar mass of Fe = 55.85 g/mol 
Molar mass of S = 32.06 g/mol

Molar mass of chalcopyrite: 
(1 x Cu) + (1 x Fe) + (2 x S) = 63.55 g/mol + 55.85 g/mol + (2 x 32.06 g/mol) = 183.54 g/mol

% composition of Cu: 
(63.55 g/mol / 183.54 g/mol) x 100% = 34.6%

% composition of Fe: 
(55.85 g/mol / 183.54 g/mol) x 100% = 30.4%

% composition of S: 
(2 x 32.06 g/mol / 183.54 g/mol) x 100% = 35.0%

Therefore, the correct answer is C, which shows that chalcopyrite is made up of 34.6% Cu, 30.4% Fe, and 35.0% S.

What Is the Percent Composition of Chalcopyrite,CuFeS2

What Is the Percent Composition of Chalcopyrite,CuFeS₂