What is potassium chloride?

What mass of potassium chloride must be added? A solution contains 1.85 g of dissolved silver.?

• A solution contains 1.85 g of dissolved silver. 1) How many moles of potassium chloride must be added to the solution to completely precipitate all of the silver? 2) What mass of potassium chloride must be added?

• Answer:

  hi there. the first step is to write the balanced equation. we dont know the silver solution so we can only use what data we have. KCl (s) + Ag (s) so 1.85g of Ag is disolved in a solution. the mol (amount) of the the silver has to be determined using the mass equation n = m /M. so substituting the mass and using the relative atomic mass of Ag 1.85g/ 108 g mol = 0.017129629 mol 1) so therefore there is 0.017129629 mol of silver.so there will be the same amount of mol in the potassium chloride for the silver to be precipitated. 2) using the mol and the mass equation and the relative molecular mass of KCl the mass needed of KCl can be determined. so K = 39 g Cl = 35 g KCl = 74 g mol using n= m/M 0.017129629 mol = m / 74g mol therefore 0.017129629 x 74 g/mol = 1.267592593 grams or 1.27 grams (2 s.f). so 1.27 grams of Potassium Chloride is needed. hope this helps.