Question

As a final problem for the week Snape thinks we should incorporate something from a previous week, hydrates perhaps. 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 is =
`LiClO_4.(H_2O)_3`

Step-by-step explanation:

`Moles =\frac {Given\ mass}{Molar\ mass}`

% of Li = 4.330

Molar mass of Li = 6.941 g/mol

% moles of Li =
`(4.330)/(6.941)` = 0.62382

% of Cl = 22.10

Molar mass of Cl = 1.00784 g/mol

% moles of Cl =
`(22.10)/(35.453)` = 0.62336

% of O = 39.89

Molar mass of O = 15.999 g/mol

% moles of O =
`(39.89)/(15.999)` = 2.49328

% of H₂O = 33.69

Molar mass of H₂O = 18.01528 g/mol

% moles of H₂O =
`(33.69)/(18.01528)` = 1.87007

Taking the simplest ratio for Li , Cl, O, and H₂O as:

0.62382 : 0.62336 : 2.49328 : 1.87007

= 1 : 1 : 4 : 3

The formula is =
`LiClO_4.(H_2O)_3`