Edexcel IGCSE Chemistry 1.5C Solubility

Practise calculating solubility in g per 100 g of solvent from evaporating-dish masses, graph readings and water volumes.

Exam points

calculate dry solute mass from evaporating dish readings before scaling to 100 g water
use graph readings and 1.0 cm3 = 1.0 g to give solubility in g per 100 g water
state temperature as a factor that changes solubility

[Maximum number: 2]

A student investigates the solubility of potassium nitrate in water.
She measures the masses of potassium nitrate that dissolve in 25 cm3 of water at different temperatures.

The table shows the student's results. One of the results is anomalous.

Table for Question 1.5C Solubility question 1 — Edexcel IGCSE Chemistry

Use your graph to calculate the solubility of potassium nitrate in g per 100 g of water at $25^{\circ} \mathrm{C}$ .
[ $1.0 \mathrm{~cm}^{3}$ of water has a mass of 1.0 g ]
solubility = g per 100 g of water

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1.5C Solubility question 1