IGCSE Chemistry: Solubility & Solubility Curves - 1.5

What is solubility?

The amount of a substance that will dissolve in a given amount/volume of solvent.

What is the unit for measuring solubility?

grams per 100 grams of solvent.

How does the solubility of solids change with temperature?

The solubility of solids generally increases as temperature increases.

How does pressure affect the solubility of gases?

Increasing pressure makes gases more soluble.

How does temperature affect the solubility of gases?

Increasing temperature generally makes gases less soluble.

What does a solubility curve show?

Solubility (g per 100 g water) against temperature.

What is plotted on the x-axis of a solubility curve?

Temperature (°C).

What is plotted on the y-axis of a solubility curve?

Solubility (g solute per 100 g H₂O).

What does it mean if a point is below the solubility curve?

The solution is unsaturated.

What does it mean if a point is above the solubility curve?

The solution is saturated plus extra solute.

How do you calculate the amount of solute that settles in a saturated solution?

Total grams minus grams in the saturated solution.

How do you scale solubility for different amounts of water?

Multiply the solubility per 100 g water by the scaling factor.

What happens to a saturated solution when it is cooled?

The difference in solubility results in the amount that crystallizes out.

How do you calculate the rate of increase in solubility?

Change in solubility divided by change in temperature.

If solubility increases by 26 g over 10°C, what is the rate of increase?

2.6 g per 100 g water per °C.