# The Gravimetric Analysis of Chloride Salt

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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
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