1. What is a solution? Bottled water is a solution.
Bottled water contains more than pure H20.
Mineral water contains naturally present minerals.
Potable water contains additives.
Distilled water is nearly mineral-free.
Carbonated water contains carbon dioxide gas.

2. Solutions
A solution is a mixture of two or more substances that is homogeneous at the molecular level.
The particles in a solution exist as individual atoms, ions, or molecules.
A solution is a mixture of solute dissolved in a solvent.

3. Colloids and Suspensions
Colloids and suspensions are NOT solutions.

4. Colloids and Suspensions
Colloid particles are formed from clusters of atoms or molecules. Colloids scatter light.
Suspensions are mixtures that settle upon standing. Suspensions scatter light.
Filtering a suspension will separate the different components.
Colloids cannot be filtered because their particles are too small.

6. What is a solution?
A solution is a special type of mixture made of minute particles that are evenly dispersed among each other. Solutions do not scatter light. Look at the diagram below. Which one is the solution?

7. Dissolving Rate
Stream or lake water may contains microscopic parasites.
Adding iodine tablets can kill microbes such as bacteria or viruses.
How can we increase the dissolving rate of the tablet?

8. Dissolving Rate
Stirring a mixture speeds dissolving. Stirring exposes fresh solvent to newly exposed solute.
Crushing a solute table increases the surface area exposed to the solvent. Every time a piece is divided the surface area increases.
Raising the temperature of the solvent will increase the dissolving rate because the particles have spread out to make room for the solute, and they are more energetic and surround the solute more readily.

9. Did You Know?
Microencapsulation is used by pharmaceutical companies in time-release medicines.
The medicines are coated with a polymer, usually from gelatin, silicone or cellulose.
Varying the thickness of the coating changes the dissolving rate.

11. Solubility
The term solubility means the amount of solute that can be dissolved in a specific volume of solvent under certain conditions.
Solutions can be unsaturated, saturated, or supersaturated. The level of saturation is determined by how much solute has been dissolved.
Several factors affect solubility:
chemical nature of the solvent
the volume of solute
temperature of the solvent

13. Solubility of Gases
The solubility of gases in liquids decreases as temperature increases.
The solubility of a gas also depends on pressure. When pressure is decreased the gas tends to come out of solution.