Question

Suppose we have a compound that is 4.330 % Li, 22.10 % Cl, 39.89 % O, and 33.69 % H2O. What is the compounds formula?

Answer 1

The formula of compound is LiClO4.3H2O

calculation

• find the mole of each element

that is moles for Li,Cl,O and that of H2O

• moles = % composition/ molar mass

For Li = 4.330/ 6.94 g/mol= 0.624 moles

Cl=22.10/35.5=0.623 moles

39.89/16 g/mol =2.493 moles

H20= 33.69/18 g/mol= 1.872 moles

• find the mole ratio by dividing each moles by smallest number of mole ( 0.624 moles)

that is for Li= 0.624/0.623= 1

Cl= 0.623/0.623=1

O = 2.493/0.623 =4

H2O= 1.872/0.623=3

Therefore the formula=LiClO4.3H2O