Gravimetric Analysis Help!!?

Question

Can someone please show me how to use gravimetric analysis and determine the gravimetric factor ect ect in a precipitation stoich problem, you jsut combine the middle of the equation or something to get the factor dont you,

If 0.2145 g sample Ni is dissolved and precipitated with excess DMG what mass of NiDMG is produced
( Molar mass DMG -116.1194 g/mol)
- solve using gravimetric factor

Btw no need to explain the basics I know all that, like how to convert to mols and grams ect ect

Answer 1

I had to read about this in order to answer your question at this web site:

http://home.um.edu.mt/chemistry/CH230/2.Analytical/CP210a.PDF

So, two moles of DMG combines with each Ni++ ion.

(0.2145 g Ni)* (1 mole Ni/58.71 g Ni) = 3.65*10^-3 mole Ni

If what you tell me is correct that DMG is 116.1194 then the Ni complex which loses 2 H+ for the Ni++ has a molecular wt of
172.8134 (please double check)

(3.65*10^-3 mole Ni)* (172.8134 g/mole) = 0.6314 g

please check for errors

Answer 2

1. The end result for sulphur will be on the lower side.the reason being that few sulphate ions will be precipitated according to the following reaction: Ba2+ + SO2-4 = BaSO4 Addition of more of the Barium Chloride in excess assures that all the sulphate is precipitated. 2.Adding silver nitrate(AgNO3) assures that chloride ions are precipitated from the solution there by minimises their interference in the above reaction.The competition for the Ba2+ is minimised.The end result could have been lowering of the weight of the precipitate obtained(BaSO4). 3.Systemic error Calibration error Linearity error of the balance