A gravimetric analysis of a water sample has to be carried out to determine the mass of Ag+ ions present. List 3 aqueous solutions that would be suitable to mix with the test sample to perform the analysis Would adding a solution of potassium nitrate be of any benefit to the analysis? After completing the analysis, the silver solid formed is sparingly soluble. How might this affect the analysis results? To determine the composition of an old coin containing silver, copper and nickel, a student dissolved the coin of mass 10·04g in nitric acid. The resulting solution was diluted with deionised water to 1000cm3 in a standard flask. 0·2mol l -1 hydrocholoric acid was to 100cm3 of this solution until precipitation of silver(I) chloride was complete. After filtration, the precipitate was washed and dried and found to have a mass of 0·620g. Calculate the percentage, by mass, of silver in the coin. Suggest how the student would test that no silver(I) ions remained in the solution. The filtrate was treated to reduce the copper(II) ions to copper(I) ions. Ammonium thiocyanate solution was added to precipitate the copper as copper(I) thiocyanate. Cu+(aq) + CNS- (aq) Cu+CNS- (s) ⟶ After filtration, drying and weighing, the precipitate was found to weigh 0·320g. Calculate the percentage, by mass, of copper in the coin. Volumetric Analysis
A gravimetric analysis of a water sample has to be carried out to determine the mass of Ag+ ions present. List 3 aqueous solutions that would be suitable to mix with the test sample to perform the analysis Would adding a solution of potassium nitrate be of any benefit to the analysis? After completing the analysis, the silver solid formed is sparingly soluble. How might this affect the analysis results? To determine the composition of an old coin containing silver, copper and nickel, a student dissolved the coin of mass 10·04g in nitric acid. The resulting solution was diluted with deionised water to 1000cm3 in a standard flask. 0·2mol l -1 hydrocholoric acid was to 100cm3 of this solution until precipitation of silver(I) chloride was complete. After filtration, the precipitate was washed and dried and found to have a mass of 0·620g. Calculate the percentage, by mass, of silver in the coin. Suggest how the student would test that no silver(I) ions remained in the solution. The filtrate was treated to reduce the copper(II) ions to copper(I) ions. Ammonium thiocyanate solution was added to precipitate the copper as copper(I) thiocyanate. Cu+(aq) + CNS- (aq) ⟶ Cu+CNS- (s) After filtration, drying and weighing, the precipitate was found to weigh 0·320g. Calculate the percentage, by mass, of copper in the coin. Volumetric Analysis