What is the empirical formula 63.0 g Rb and 5.90 g O.

Explanation:

1st convert given data into % per 100wt...

Total system mass = 63.0g + 5.90g = 68.9g

%Rb = 63.0g/68.9g x 100% = 91.4% per 100wt

%O  =  5.9g / 68.9g x 100% = 8.6%

Then follow the following sequence of calculations...

% => grams => moles => mole ratio => reduce to smallest whole no ratio => empirical ratio => empirical formula

%Rb = 91.4% => 91.4g/ 85.5g·mol⁻¹ =>1.069mole

%O  =   8.6% =>  8.6g/16g·mol⁻¹ => 0.5375mole

Rb:O => 1.069 : 0.5375

Reduce by dividing by the smaller mole value

1.069/0.5375 : 0.5375/0.5375 => 2 : 1 <=> empirical ratio

∴ Empirical Formula => Rb₂O

- aluminum and copper chloride.

- the chloride ion to separate the aluminum from the oxygen so that the aluminum can react with the copper ions (and the water molecules).