1. C HEMICAL BASIS OF L IFE Please Take out your notebooks

2. ATB Get a text book Take out your body systems notes. Study them!!!

3. V OCABULARY Atoms are made up of protons, electrons, and neutrons. Elements are pure substances that consists entirely of one type of atom. Compound is a substance formed by the chemical combination of two or more elements in definite proportion. Molecule is the result of atoms that are joined together by covalent bonds.

4. B ONDING Ionic bonds are formed when one or more electrons are transferred from one atom to another. Covalent bonds are formed when electrons are shared between atoms.

5. E LEMENTS YOU NEED TO KNOW C Ca Cl F Fe H I K Mg N Na O P S Zn

6. E LEMENTS YOU N EED TO K NOW C = Carbon Ca = Calcium Cl = Chlorine F = Fluorine Fe = Iron H = Hydrogen I = Iodine K = potassium Mg = magnesium N = Nitrogen Na = Sodium O = Oxygen P = Phosphorus S = Sulfur Zn = Zinc

7. C REATE F LASHCARDS FOR THESE TERMS Supersaturated Unsaturated Saturated Soluble Insoluble Suspension Dissolve Solution Colloid Solute Solvent Alloy

8. W ATER M OLECULES Hydrogen and oxygen are held together by polar covalent bonds. Polar because there is an uneven distribution of electrons between oxygen and hydrogen. Multiple water molecules are held together by hydrogen bonds.

11. P ROPERTIES OF WATER THAT ARE ESSENTIAL TO LIFE Adhesion and cohesion Capillary action Water has a high boiling point Water has a high heat of vaporization Water has a high specific heat Density Universal solvent Video: Crash course Properties of water

12. P ROPERTIES OF WATER Adhesion An attraction between molecules of different substances. Cohesion Attraction between molecules of the same substance. Surface Tension- a measure of how difficult it is to stretch or break the surface of a liquid.

13. C APILLARY A CTION Water has the ability to “climb” structure Uses both adhesion and cohesion together to climb. Question: Why is capillary action extremely important to plants?

14. C APILLARY ACTION Water uses adhesive forces to stick to the sides of the stem. The water is pulled upwards from the roots by cohesive forces because the water molecules are sticking to each other. Adhesion=water to surfaces Cohesion= water to water

15. W ATER HAS A HIGH BOILING POINT Water is one of the few substances that remain a liquid at such a large range of temperatures (O- 100 °C). A large amount of energy must be invested to overcome the hydrogen bonds in liquid water to change it to the gas phase.

16. H IGH H EAT OF VAPORIZTION Water can take a lot of heat without its temperature rising much. This plays a huge part in the climate, because it means that oceans take a long time to warm up.

17. W ATER HAS A HIGH H EAT C APACITY Specific heat- A measure of heat capacity, is the heat that is required to raise the temperature of 1 gram of water 1 degree Celcius. Changes temperature more slowly than other compounds that gain or lose energy. Question : How is water’s high heat capacity involved with climate control.

18. H EAT CAPACITY AND CLIMATE Water absorbs the heat of the sun all day. At night it releases the heat to keep temperatures steady The earth is covered with 70+% of water. Question : How can you use the properties of water to explain the extreme temperature changes in the desert?

19. D ESERT C HANGES ? There is very little water in the desert. The water is what helps the temperatures to remain steady. Without the water to absorb the heat during the day, there is no release of heat at night. Therefore the temperature at night drops.

20. I MPORTANCE OF H EAT C APACITY OF WATER The temperature of water rises slowly with the addition of heat. The water that covers most of the Earth’s surface keeps temp fluctuations within limits that allow living organisms to survive. Can have profound effect on climatic conditions When water warms only a few degrees, a large body of water can absorb and store a large amount of heat from the sun during the day. At night and during winter, the gradual cooling of water can warm the air.

21. D ENSITY OF WATER The density of ice is almost ten times less than the density of liquid water. This causes ice to float. This allows animals in aquatic habitats to survive through the winter.

22. U NIVERSAL S OLVENT Ability to dissolve materials Water is considered to be the universal solvent. More substances dissolve in water than any other liquid.