A 3.000 g sample of a compound containing only carbon, hydrogen and cobalt was analyzed and found to contain 1.453 g of carbon and 0.122 g of hydrogen. If the formula mass (molar mass) of the compound is approximately 372 g/mol, what is its chemical formula?

C₁₅H₁₅Co₃

Explanation:

Compound = Carbon+ Hydrogen + Cobalt

Mass of carbon = 1.453 g

Mass of Hydrogen = 0.122 g

Mass of Cobalt = 3 - 1.453 - 0.122 = 1.425 g

Dividing all through b their molar masses

Carbon = 1.453 / 12 = 0.1211

Hydrogen = 0.122 / 1 = 0.122

Cobalt = 1.425 / 58.9 = 0.02419

Divide all through by the smallest number (0.02419)

Carbon = 0.1211 / 0.02419 = 5

Hydrogen = 0.122 / 0.02419 = 5

Cobalt = 0.02419 / 0.02419 = 1

The empirical formular = C5H5Co

(C5H5Co)n = 372

[(12 * 5 ) + (5 * 1 ) + 58.9]n = 372

n = 372 / 123.9 = 3

Chemical formular;

C₁₅H₁₅Co₃

your answer would be “dry”