The Gravimetric Analysis of Chloride Salt

1469 WordsFeb 22, 20136 Pages
Gravimetric Analysis of a Chloride Salt CHEM 1001 Purpose: To illustrate typical techniques used in gravimetric analysis by determining quantitatively the chloride content in an unknown soluble salt. Theory: AgCl(s) is a very insoluble solid, yet still does have some solubility. Because of these traits, the following reaction is able to occur: Ag+(aq) + Cl−(aq) → AgCl(s) . This reaction is able to occur in both directions. When a soluble silver salt such as AgNO3 is added to a solution containing Cl−(aq) ion, then the added Ag+(aq) precipitates as AgCl(s) until all the chloride is consumed. For this particular reaction K sp = 1.6 x 10−10. The reason why the solution is precipitated in an acidic medium become this causes the…show more content…
As the crucible is heated and the liquid inside the precipitate begin to evaporate the purple fades it it becomes a greyish-white colour. True Percentage of Cl-= 56.52% ms1= 0.1222g Volume of 0.1M AgNO3 = [(0.1222g x 0.55)/35.5g/mol]/0.1M + 5mL Volume of 0.1M AgNO3 = 0.0189323L + 5mL Volume of 0.1M AgNO3 = 18.9323mL + 5mL Volume of 0.1M AgNO3 = 23.9323mL ms2= 0.1492g Volume of 0.1M AgNO3 = [(0.1492g x 0.55)/35.5g/mol]/0.1M + 5mL Volume of 0.1M AgNO3 = 0.0231155L + 5mL Volume of 0.1M AgNO3 = 23.1155mL + 5mL Volume of 0.1M AgNO3 = 28.1155mL mc1= 30.6795g mc2= 33.2337g T= 105°C th= 30 minutes tc1= 5 minutes mc1= 30.9907g mc2= 33.5634g tc2= 5 minutes mc1= 30.9218g mc2= 33.5664g Mass of Cl- in precipitate (1) mass in precipitate= (mass of crucible and sample) - (mass of crucible) mass in precipitate= 30.9218g - 30.6795g mass in precipitate= 0.2423g Percent of Cl- in original sample (1) moles of Cl- in sample= (mass of AgCl)/(MW of AgCl) moles of Cl- in sample= (0.2423g)/(143.321g/mol) moles of Cl- in sample= 0.001690611mol mass of Cl- in sample= (0.001690611mol)(35.453g/mol) mass of Cl- in sample= 0.059937217g % of Cl- in original sample= [(mass Cl-)/(mass of sample)] * 100 % of Cl- in original sample= (0.059937217g / 0.2423g) * 100 % of Cl- in original sample= 24.74% Mass of Cl- in precipitate (2) mass in precipitate= (mass of crucible and sample) - (mass of crucible) mass in
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