JAMB - Chemistry (2025 - No. 51)
On heating 12.5g of saturated solution to dryness at 60\(^0\)C, 2g of anhydrous salt was recovered, calculate its solubility in grams per 100g of water.
16.0
4.0
2.0
20.0
Vysvětlení
Solubility is expressed as the mass of solute per 100g of solvent. It can be expressed mathematically below as:
Solubility = \(\frac{mass of solute}{mass of solvent}\) x \(\frac{100}{1}\)
= \(\frac{mass of salt}{mass of water}\) x \(\frac{100}{1}\)
Mass of salt = 2g
Mass of water = Mass of solution - mass of salt = 12.5 - 2 = 10.5g
Solubility = \(\frac{2}{10.5}\) x \(\frac{100}{1}\)
= 19.0476
= 19.05 g