CHEMISTRY NOTES - MATTER Matter – anything that has mass and volume. Matter is made up of tiny particles called atoms and molecules. Phases of matter: solid, liquid, gas. Video Heat is the cause of phase changes. More heat means faster moving particles, less attraction between particles, and more space between particles. HEAT

Phase Changes Melting: solid becomes a liquid ( 0 ºC for water ) Freezing: liquid becomes a solid ( 0 ºC for water ) Boiling: liquid becomes a gas ( 100 ºC for water ) Condensation: gas becomes a liquid ( 100 ºC for water )

Physical Change - a change in size, shape or phase of a substance. - Examples: crumpled paper, broken glass, melting, freezing, boiling Chemical Change - a NEW substance is formed, with NEW properties. Cannot be physically separated. - How can you tell? 1) Temperature change 3) Gas formation 2) Color change 4) 2 liquids form a solid

Element - the simplest form of matter. ~ 110 known elements in the universe. Atom - a single particle of an element. - example: 1 atom of Sodium (Na)

- Example: a water molecule is two A Molecule is two or more atoms combined. A single particle of one compound. - Example: a water molecule is two Hydrogen atoms and one Oxygen atom. A Compound is two or more elements that can’t be physically separated, making a certain type of molecule. - Examples: Salt, Water, carbon dioxide A Mixture is two or more substances that can be separated, and do not form a new compound. - Examples: sand + gravel, oil + water, salt + water

Chemical Equation - a summary of a chemical change (reaction). Chemical Formula – a shorthand way to show the number and type of atoms in a substance. - examples: H2O O2 H2SO4 Chemical Equation - a summary of a chemical change (reaction). * Some reactions require energy 6CO2 + 6H2O   6O2 + C6H12O6 * Some reactions release energy 6O2 + C6H12O6 6CO2 + 6H2O + energy The Law of Conservation of Mass states that matter can never be created or destroyed. This can be proven by counting up the number of atoms of each element on both sides of the equation. The numbers will be equal. energy

Acids and Bases Acid - any compound that produces hydrogen ions (H+) in water. The more H+ ions produced, the stronger the acid. Base – Any compound that produces hydroxide ions (OH-) in water. The more OH- ions produced, the stronger the base. An ion is simply an atom with a positive or negative charge. The pH scale tells how acidic or basic a substance is. · measures H+ concentration on a scale of 0 to 14 · pH of less than 7 is acidic, lower pH = more acidic · pH of more than 7 is basic, higher pH = more basic · pH of 7 is neutral, pH of water = 7 Litmus paper is an indicator, a substance that changes color when it comes in contact with an acid or base.

Structure of an ATOM Nucleus - the center of the atom Proton - positively charged (+) particle in the nucleus. Neutron - particle in the nucleus with no charge. Electron - negatively charged particle (-) outside of the nucleus. http://www.colorado.edu/physics/2000/applets/a2.html

- The Atomic Number is the number of protons (electrons usually the same) - The Atomic Mass is protons plus neutrons - To find the number of Neutrons… Atomic Mass – Atomic Number = Neutrons Element Symbol Atomic # Atomic Mass P E N Oxygen O 8 16 8 8 8 Iron Fe 26 56 26 26 30

CHEMISTRY NOTES – ENERGY All Matter has energy Energy has many different forms Kinetic energy (motion) Potential energy (stored) - Mechanical - Mechanical - Electrical - Electrical - Heat - Gravitational - Light - Chemical - Sound

Mechanical energy is the energy of a moving object, caused by a force. Ex: engines, a person running, throwing a ball Electrical energy is the flow of electrons toward a positive charge. Needs a conductor like metal. Ex: extension cord, power line Heat energy is the movement of the atoms/molecules of a substance. Ex: boiling water Light energy is the movement light rays. Ex: sunlight, lamp Sound energy is carried by sound waves. Ex: any noise

Chemical energy is stored in the chemical bonds of atoms and molecules. Ex: Batteries, gasoline, food Gravitational energy is stored in objects because of their position. Ex: a leaf on a tree The Law of Conservation of Energy states that energy is never created or destroyed, it simply changes form. - Example: a light bulb changes electrical energy to light and heat energy.

Flashlight Energy Transformation: When a flashlight is turned on, energy changes from potential-chemical energy (battery), to electrical energy (circuit), to light and heat energy (bulb). Flashlight Energy Transfer: When a flashlight is turned on, energy moves from the battery to the circuit wires, to the bulb, and finally to the environment.