Answer to Question #203604 in General Chemistry for nurul

Question

Suppose you wanted to analyse the amount of metal in alloy. For example, you might want to determine the nickel (Ni2+) content in alloy material.

(a) Using gravimetric analysis, propose precipitating method to analyze nikel (Ni2+) in alloy and write 8 steps required during the precipitation. Also suggest an appropriate solvent and its ratio to dissolve the mixture. Here we recommended to use dimethylglyoxime (H2DMG) as organic precipitating agent. (10 Marks)

(b) Suppose the nickel had been precipitated from the alloy (2.0980g) using dimethylglyoxime (H2DMG) as organic precipitating agent and giving a precipitate of complex nickel dimethylglyoxime (Ni(HDGMG)2) weighing 0.2370g. Calculate the percentage weight of nickel (Ni2+) in the alloy sample. (5 Marks)

Answer 1

a) Chemical precipitation is the process of conversion of a solution into solid by converting the substance into insoluble form or by making the solution a super saturated one.

Chemical precipitation, formation of a separable solid substance from a solution, either by converting the substance into an insoluble form or by changing the composition of the solvent to diminish the solubility of the substance in it. The distinction between precipitation and crystallization lies largely in whether emphasis is placed on the process by which the solubility is reduced or on that by which the structure of the solid substance becomes organized.

b) $=\frac {0.99}{0.99+0.237}×100 =80.6\%$