The molecular formula of hydrate : CaCl₂.6 H₂O
So there are 6 molecules of H₂O
Given
54.7g CaCl₂ and 53.64 g H₂O
Required
The number of molecules H₂O
Solution
mol CaCl₂ :
= mass : MW
= 54.7 : 111 g/mol
= 0.493
mol H₂O :
= 53.64 : 18 g/mol
= 2.98
mol ratio H₂O : CaCl₂ :
= 2.98/0.493 : 0.493/0.493
= 6 : 1