Question

A 0.1987 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^-1). When the precipitate was rinsed, dried, and cooled, it was determined to have a mass of 0.1763 g. Calculate the mass of nickel in the precipitate and the percent (by mass) of nickel in the original (unknown) salt sample.

Please. Please show me detail work so that I understand this problem.If you know how to use an ICE table please do so since it allows me to understand it better.

Answer 1

mass of precipitate of nickel(II) dimethylglyoxime complex isolated = 0.1763 g

nO of mole of precipitate of nickel(II) dimethylglyoxime = 0.176/288.917

          = 6.09*10^-4 mol

1 mole nickel(II) dimethylglyoxime = 1 mole Ni

nO of mole of nickel present in precipitate = 6.09*10^-4 mol

mass of nickel present in precipitate = 6.09*10^-4*58.7 = 0.0357 g

percent of Ni in original salt sample = 0.0357/0.1987*100 = 18%