Question

Calculate the formula masses of the following compounds :

Calcium carbonate

Answer 1

Atomic mass of aluminium = 27 u

Atomic mass of oxygen = 16 u

Formula mass of Al₂O₃ can be calculated as follows:

Formula mass of Al₂O₃ = Mass of two Al atoms + Mass of three O atoms

= 2 × 27 + 3 × 16   

= 54 + 48

= 102

Therefore, the formula mass of Al₂O₃ is 102 u.