Asolution contains an unknown mass of dissolved silver ions. when potassium chloride is added to the solution, a white precipitate forms. the precipitate is filtered and dried and then found to have a mass of 245 mg. what mass of silver was in the original solution? (assume that all of the silver was precipitated out of solution by the reaction.)

Mass of silver in the original solution = 0.1845 g

Explanation:

The precipitate must be of silver chloride. So,

Given that:

Mass of silver chloride = 245 mg = 0.245 g ( 1 mg = 0.001 g )

Molar mass of silver chloride = 143.32 g/mol

The formula for the calculation of moles is shown below:

Thus,

From the reaction,  

1 mole of AgCl is formed from 1 mole of silver

So,

0.00171 mole of AgCl is formed from 0.00171 mole of silver

Moles of silver = 0.00171 moles

Molar mass of silver = 107.8682 g/mol

Mass = Moles*Molar mass = 0.00171 moles*107.8682 g/mol = 0.1845 g

Mass of silver in the original solution = 0.1845 g