Interpreting Solubility Curves

Unit 9: Solutions

What are solubility curves?• Changing the

temperature and pressure changes the amount of solute that can dissolve.

• Solubility measures the amount of solute dissolved in a solvent at a certain temperature

• Solubility curves show the solubility (grams per 100g of water) at different temperatures

What are solubility curves?

• Points ON the curve show saturated soln

• Points ABOVE the curve show supersaturated soln

• Points BELOW the curve show unsaturated soln

What is the solubility of solids?• For solids…• As temperature increases solubility increases

• As temperature decreases solubility decreases

• This is known as directly proportional – they both do the same thing!

What is the solubility of solids?• Which substances

are solids?– KNO3

– NH4Cl– NaCl– K2SO4

– KClO4

What is the solubility of gases?• For gases…• As temperature increases solubility decreases

• As temperature decreases solubility increases

• This is known as inversely proportional – they do DIFFERENT things!

What is the solubility of gases?• Which substance is

a gas?– Li2SO4

Practice• Can more sugar dissolve in tea when it

is hot or cold? Explain your reasoning.

• If it gets too hot on a summer day, why might many fish die resulting in fish kills?