Question

Beryl is a mineral which contains 5.03% Be, 10.04% Al, 31.35% Si, and 53.58% O. What is the simplest formula for beryl?

Answer 1

Let the mass of Beryl be 100 g

So the amount of Be = 5.03 g

Number of moles of Be = 5.03 / 9 = 0.56 moles

Amount of Al = 10.04 g

Number of moles of Al = 10.04 / 27 = 0.37 moles

Amount of Si = 31.35 g

Number of moles of Si = 31.35 / 28.08 = 1.12 moles

Amount of O = 53.58

Number of moles of O = 53.58 / 16 = 3.35 moles

Dividing the number of moles by a common value 0.19 , we get the ratio of elements as 3:2:6:18

So the simplest formula of Beryl will be : Be₃Al₂Si₈O₁₈