Answer:
Step-by-step explanation:
Molecular weight of Be(OH)₂ = 43 .
One mole contains 2 atoms of oxygen . Atomic weight of oxygen is 16 so 2 atoms will have mass of 32 u .
So 43 g of Be(OH)₂ contains 32 g of oxygen .
100 g of Be(OH)₂ contains 32 x 100/ 43 g of oxygen
= 32 x 100/ 43 g of oxygen
= 74.42 % .