1. Wonderful World of Water

2. What makes water so great?
Water is considered the “Universal Solvent” due to its unique properties. - hydrogen and oxygen form polar covalent bonds - this makes the water molecule bend and have a definite positive and negative ends - the positive hydrogen ends form “hydrogen bonds” with the oxygen of other water molecules. This leads to capillary action, high surface tension, and high specific heat.

3. Properties of Water continued…
Surface Tension– the unbalanced cohesive forces between the water molecules at the surface. Water has a high surface tension due to the hydrogen bonds.
Capillarity is a result of the attractive forces between the molecules (cohesion) and a result of the attractive forces between the molecules and the container (adhesion).
Specific heat is the amount of heat needed to raise the temperature of one gram of a substance one Celsius degree. It takes 4.18 Joules of heat to raise the temperature of 1 gram of water 1°C.

4. Properties of Water continued…
Universal Solvent due to the fact that many ionic and covalent compounds dissolve easily in it.
Water is found naturally in 3 states: solid, liquid, and gas. When water is cooled to about 4°C, instead of the volume decreasing, it actually begins to increase. Therefore, the solid form of water, ice, is less dense than water in its liquid form.

5. Importance of water to life.
Since ice floats, many living aquatic organisms can thrive during the winter season.
The high specific heat of water allows water to store large amounts of heat energy without increasing the temperature of the water.
All biochemical reactions in cells occur in aqueous solutions.
Water cools animals off through evaporative cooling, and serves to transport minerals and cool plants through transpiration.

6. Other importance of water…
Water has different impacts to its surroundings when it freezes and expands or when it is in motion.
Flowing water weathers rocks, and moves minerals to different locations.
Freezing and cooling expands water in rocks, causing them to break apart.

7. Solutions
Solutions are homogeneous mixtures of two or more substances.
They are not chemically combined, they can be separated by physical means
Solvent  substance in the larger amount
Solute(s)  substance dissolved in the solvent
Aqueous Solutions are solutions with water as the solvent.

8. Ionic Solutions
If a solution contains ions, then the solution is called an electrolyte solution. Electrolytes are conductors of electricity.
Metallic salts dissociate into ions when dissolved in water.
Most acids are electrolytes.
Substances that do not dissociate into ions, but retain their molecular composition, are called nonelectrolytes, and do not conduct an electrical current. Sugar solution is an example.

9. Amounts of Solutes
If a solution contains the maximum amount of solute, then the solution is said to be saturated.
If more solute could be dissolved into the solvent, then the solution is said to be unsaturated.
A solution can hold more solute than it normally does under certain conditions. When this happens, the solution is called supersaturated.

10. Describing Solutions
Solutions are described by how much solute is dissolved in a solvent.
If there is a large amount of solute relative to the solvent, then the solution is concentrated.
If there is a small amount of solute relative to the solvent, then the solution is dilute.

11. Other Solutions
Not all solutions have a solid as a solute and water as the solvent.
A gas can be a solute, as well as a liquid.
Examples:
Soda gas dissolved in water
Ethyl Alcohol dissolved in water
Air is another solution, containing gas and gas. Depending on the environment, it could be solids and gas.
Metal alloys are solid in solid solutions.
Steel and brass