1. Chapter 6
Part 2
Pages

2. Compounds and Bonding
Page 145
Compound- a substance that is composed of atoms of two or more different elements that are chemically combined

3. Most elements in nature are found combined in the form of compounds
How and why do atoms combine?
Combine when the resulting compound is more stable than the individual atoms.
For many elements, an atom becomes more stable when its outermost energy level is full- by sharing electrons with other atoms

4. Sharing electrons

5. Page 146
Covalent bond- force that holds atoms together when they are sharing electrons
Most compounds in organisms have covalent bonds.

6. Molecule A group of atoms held together by covalent bonds.
No overall charge
Example-molecule of water

7. Chemical formula Page 147 Use the chemical symbol for atoms
Subscripts represent the number of atoms present
Example:

8. Ionic Bonds
An atom gains or loses electrons, it has an electrical charge (charged particle) and will assume the name ION.
atoms combine with each other by gaining or losing electrons in their outer energy levels- not sharing of electrons
Example page 147- sodium chloride

9. Chemical Reactions Page 147
Occur when bonds are formed or broken, causing substances to recombine into different substances
All of the chemical reactions that occur within an organism are referred to as that organism’s metabolism
Consists of reactants and products

10. Chemical Equations Reactants Products
Number before each formula indicates the number of molecules of each substance
Subscripts in a formula indicate the number of atoms of each element in a molecule of the substance
Equations must always balance

13. Mixtures
Page 148
A mixture is a combination of substances in which the individual components retain their own properties
Example- mixing sand and sugar crystals

14. Solutions
A mixture in which one or more substances (solutes) are distributed evenly in another substance (solvent)

15. Acids and Bases Page 149
Chemical reactions can occur ONLY when the conditions are right
Variables may include (but not limited to):
Temperature
Energy availability
Solute concentration pH

16. A measure of how acidic or basic a solution ispH
A measure of how acidic or basic a solution is

17. What is an acid? Any substance that forms hydrogen ions in water
Reacts with most metals
Tastes sour
Frequently feels sticky
Examples: grapefruit, oranges, lemon, tomato, milk

18. What is a base? Any substance that forms hydroxide ions in water
Feels slippery
Tastes bitter
Examples: egg, antacid, ammonia, cleaners

20. Acids and Bases
A scale with values ranging from 0 to 14 is used to measure pH
0-6 acidic
7 neutral (pure water)
8-14 basic

21. Acids and Bases Video 8 minutes

22. BIG PICTURE
An acid is any substance that form hydrogen ions (H+) in water
A base is any substance that forms hydroxide ions (OH-) in water
Mini lab 6.1

23. LAB- Analysis Questions
1. What would happen to our bodies if blood pH was changed or altered?
2. The pH of stomach acid is 2, why is this both good but possibly destructive to our bodies?
3. What could happen to our local environment if a company pumped materials into the atmosphere which created a drastic pH change in the rain water?