the solubility of a solid is normally defined as the mass in grams which will dissolve in 100g of solvent to form a saturated solution at a given temperature.
Question: an evaporating dish weighed 11.68g; partly filled with a saturated solution of potassium chloride at 20 degree celcius it weighed 27.89g, and after carful evaporation to dryness it weighed 15.81g.
Calculate the solubility of potassium chloride at 20 degree celcius?
Solution
weighed dish = 11.68g
weighed dish + solution = 27.89g.
weighed dish + dry potassium chloride = 15.81g
Therefore: mass of water = loss due to evaporation =
(27.89 – 15.81)g = 12.08g
Now
Mass of potassium chloride = (15.881 – 11.68)g = 4.13g
Therefore 12.08g of water dissolved 4.13g of potassium chloride
Our equation will 100g of water will 4.13 x 100/12.08g
= 34.2g of potassium chloride.
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