EN
Intu LabUnderstanding through experience
All courses
Chemistry · Understanding manipulation

Interpreting solubility diagrams

Plan for saturation and the possible presence of a solid deposit.

Reading · approximately 4 min2 relationships explainedquiz · 3 questions
01 · The scientific principle

What is happening?

At a given temperature and pressure, solubility limits the quantity of a solute that can dissolve in a solvent. A saturated solution can coexist with an excess of solid.

The axis of the diagram specifies the convention: grams per 100 g of water, grams per liter of solution or molar concentration. These quantities are not interchangeable without conversion.

02 · Relationships to know

The formulas, with their conditions.

mmax = S(T) × meau / 100

S: g of solute per 100 g d water; meau and mmax: g.

Use when: Only for a diagram expressed according to this convention.

mprécipité = max(0, minitial − mdissous à Tfinal)

Masses in the same unit.

Use when: Cooling at constant solvent quantity, without reaction or evaporation.

03 · From laboratory to industry

Where is this principle used?

Crystallization plant

Choose cooling to recover a solid.

Pharmaceutical and salt industry

Separate and purify dissolved products.

What to observe in the experiment

Keep the same mass of water and cool a saturated solution: compare the initial and final solubilities before estimating the deposition.

To learn more

References and readings

This sheet explains the principles and their assumptions. Educational simulation can simplify the process; an industrial model requires suitable data and validation.

04 · Your turn

Have you understood the essentials?

Only one correct answer per question. Answer all three questions, then view the answer key.

1. S = 20 g per 100 g of water: how much can be dissolved in 50 g of water?
2. A saturated solution is…
3. Why read the axis unit?
Intu Lab · Understanding sheet · Kimba Christian