Answer Happy

1. When the sample is placed in the oven, the alcohol and water evaporate. List all other chemicals, including spectator ions that must be washed from the sample before it is dried. 2. A 0.2016 g sample of an unknown Ni(II) salt was put into solution and properly treated to form the solid nickel(II) dimethylglyoxime complex (molar mass=288.917 g mol ). When the precipitate was rinsed, dried, and cooled, it was determined to have a mass of 0.1991 g. Calculate the mass of nickel in the precipitate and the percent (by mass) of nickel in the original (unknown) salt sample. 3. When a solution containing silver ions is mixed with another solution containing chloride ions, a precipitate of silver chloride forms. When 25.00 ml of a silver nitrate solution is mixed with an excess of a sodium chloride solution, all of the silver ion is precipitated as silver chloride. The solid is collected, washed, dried, and found to have a mass of 1.0237 g. Calculate the molarity of the original silver nitrate solution.