1. Chapter 2 Lecture Outline See PowerPoint Image Slides
for all figures and tables pre-inserted into
PowerPoint without notes.

2. Matter, Energy, and Life
Matter is anything that has mass and occupies space.
Energy is the ability to do work.
There are two types of energy:
Potential energy
Stored energy, available to do work
Kinetic energy
Energy of motion
Potential energy can be converted to kinetic energy to do work.

3. Law of Conservation of Energy
Energy is never created or destroyed.
The first law of thermodynamics
Energy can be converted from one form to another, but the total energy remains constant.
An object at the top of a hill has potential energy based on its location.
When the object rolls down the hill, the potential energy is converted to kinetic energy.

4. Forms of Energy There are five forms of energy: Mechanical energy
Energy of movement
Nuclear energy
Energy from reactions involving atomic nuclei
Electrical energy
Flow of charged particles
Radiant energy
Energy in heat, light, x-rays and microwaves
Chemical energy
Energy in chemical bonds

5. What is the nature of matter?
Atoms
The smallest units of matter that can exist separately
Elements
Chemical substances composed of the same kind of atoms
Listed on the periodic table
Each element is represented by a symbol of one or two letters.
The principal elements that comprise living things are:
C, H, O, P, K, I, N, S, Ca, Fe, and Mg.

6. The Periodic Table of the Elements

7. Atomic Structure Atoms are composed of: The atomic nucleus Electrons
Protons - positively charged
Atomic number-the number of protons
All atoms of the same element have the same number of protons.
Neutrons – no charge
Electrons
Orbit the nucleus in energy levels
Are constantly in motion

8. Atomic Structure

9. Elements
Atoms of the same element have equal numbers of electrons and protons.
Thus, they have a neutral charge.
Isotopes
Atoms of the same element that have different numbers of neutrons.
Atomic weight-the average of all of the isotopes in a mixture.
Mass number
The sum of protons and neutrons in the nucleus.

10. Isotopes of Hydrogen

11. Electrons Electrons occupy specific energy levels around the nucleus.
Electrons closest to the nucleus have the lowest energy.
Energy levels hold specific numbers of electrons.
The first energy level can have up to 2 electrons.
All other energy levels can have up to 8 electrons.
Atoms seek to have a full outer energy level.
Atoms that have full outer energy levels are inert.
Other atoms seek to fill their outer energy levels through chemical bonds.

12. Electrons

13. The Formation of Molecules
Molecules consist of two or more atoms joined by a chemical bond.
A compound is a chemical substance made of two or more elements combined in chemical bonds.
The formula of a compound describes the nature and proportions of the elements that comprise the compound.
H2O

14. Molecules and Kinetic Energy
Molecules are constantly in motion.
Temperature is a measure of the average speed of the molecules in a substance.
The greater the speed, the higher the temperature.
Measured in Fahrenheit or Celsius
Heat is a measure of the total kinetic energy of molecules.
Measured in calories (amount of heat that will raise 1g of water 1 degree Celsius).
Heat and Temperature are related.
Add heat energy to a substance and the molecules will speed up, and the temperature will rise.

15. Kinetic Energy, Physical Changes and Phases of Matter
Three phases of matter
Solid
Liquid
Gas
The phase in which a substance exists depends on its kinetic energy and the strength of its attractive forces.
Solids-strong attractive forces, low kinetic energy, little to no molecular movement.
Liquid-enough kinetic energy to overcome the attractive forces; more molecular movement.
Gas-high kinetic energy, little to no attractive forces; maximum movement.