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

Answer:

The  formula is = $LiClO_4.(H_2O)_3$

Explanation:

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

% of Li = 4.330

Molar mass of Li = 6.941 g/mol

% moles of Li = $\frac{4.330}{6.941}$ = 0.62382

% of Cl = 22.10

Molar mass of Cl = 1.00784 g/mol

% moles of Cl = $\frac{22.10}{35.453}$ = 0.62336

% of O = 39.89

Molar mass of O = 15.999 g/mol

% moles of O = $\frac{39.89}{15.999}$ = 2.49328

% of H₂O = 33.69

Molar mass of H₂O = 18.01528 g/mol

% moles of H₂O = $\frac{33.69}{18.01528}$ = 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 = $LiClO_4.(H_2O)_3$