Question

The formula unit mass of $CaC{l}_2$ is:

• A. 105 u
• B. 111 u
• C. 100 u
• D. 121 u

Answer 1

The correct option is B 111 u

Formula unit mass is defined as the sum of the atomic masses of all atoms that are present in a formula unit of the given compound.

Atomic mass of Ca = 40 u
Atomic mass of chlorine = $35.5\times 2=71u$
Formula unit mass = 40 + 71 = 111 u

Hence, option (b) is correct