Question

What is the formula mass of FeCl3?

a) 54.94 g/mol
b) 162.20 g/mol
c) 55.85 g/mol
d) 162.91 g/mol

Answer 1

The formula mass of FeCl3 is calculated by adding the molar masses of iron and chlorine atoms, giving a total of 162.20 g/mol.

Step-by-step explanation:

To calculate the formula mass of FeCl3, we need to add together the atomic masses of one Fe atom and three Cl atoms. The molar mass of iron (Fe) is 55.85 g/mol, and the molar mass of chlorine (Cl) is 35.45 g/mol. Hence, the calculation for FeCl3 is as follows:

Fe: 1 × 55.85 g/mol = 55.85 g/mol

Cl: 3 × 35.45 g/mol = 106.35 g/mol

Add these together to find the formula mass of FeCl3:

55.85 g/mol (Fe) + 106.35 g/mol (Cl) = 162.20 g/mol

This matches option b, indicating that the correct formula mass of FeCl3 is 162.20 g/mol.