2 Parts to All Solutions

• Solvent – The part of the mixture present in the greatest amount (part doing the dissolving).

• Solute – The part or parts of the mixture present in the lesser amount (part being dissolved).

water-solventsugar-solute

greatest amount

water-solvent

lesser amount

sugar-solute

the amount of solute that will dissolve in a given amount of solvent at a specific temperature and pressure

What is solubility?

What is dissolving?

Dissolving happens when the solvent, usually water molecules, collide with the solute and pull it apart piece by

piece.

• saturated – a solution is holding the maximum amount of solute possible, and more solute added would collect at the bottom.• unsaturated – more solute can be added and will still dissolve.• super saturated – more solute than should be possible at that temperature and pressure is dissolved (Ex: ‘Sweet’ tea)

3 types of solutions (based on the amount of

solute)

How can we change the amount that will dissolve?

The solubility of a substance (the amount that will dissolve) depends on three factors:

1. Temperature2. Pressure3. Type of substance

To increase the amount of solid that will dissolve in a liquid you would need to

- Increase the temperature- Decrease the pressure

Can we make something dissolve faster?

Stirring/shaking: brings more fresh solvent in contact with more solute.

Crushing/grinding: increases the surface area.

Increasing the temperature: speeds up the movement of the solvent particles creating more collisions with the solute.

Can we make something dissolve faster?

Stirring/shaking: brings more fresh solvent in contact with more solute.

Crushing/grinding: increases the surface area.

Increasing the temperature: speeds up the movement of the solvent particles creating more collisions with the solute.

water-solventsugar-solute

In the real world!

When making tea (even iced tea) you have to steep the tea bag in boiling hot water.

Timed release capsules control how fast medicine dissolves.

Can a gas dissolve in a liquid?

Gas solutes are all around you!

– CO2 in coke

– Dissolved O2 in lakes, rivers, oceans

Fish have gills which absorb oxygen from the water…humans obviously do not!

The solubility of a gas also depends on temperature and pressure.

– As temperature decreases, more gas will dissolve.

– As pressure increases, more gas will dissolve.

How can a gas dissolve in a liquid?