A sample of mixture of and was dissolved in water and mixed thoroughly with portion of . After reaction, the solid which now contains and was filtered, dried and weighed to be . What was the by

Question

A  sample of mixture of  and  was dissolved in water and mixed thoroughly with  portion of . After reaction, the solid which now contains  and  was filtered, dried and weighed to be . What was the  by weight of  in the mixture?

Canvas Classes · Accepted Answer

Strategy:
 When excess  is treated with Bromide ions, the Bromide completely displaces Chloride due to the lower solubility () of . The increase in the mass of the solid phase is due to the substitution of heavier Bromide atoms () for Chloride atoms ().

Step 1: Relate mass increase to Bromide moles
Reaction: .
For every 1 mole of  reacting, mass increases by .
Actual mass increase .

Step 2: Calculate mass of } \ce{CuBr2}
Molar mass of .
Since 1 mole  contains 2 moles of :

Step 3: Calculate

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