Warm Up How do the arrangement and behavior of particles of matter differ in solids, liquids, and gases?

Classification of Matter Unit 3 Matter/Change Classification of Matter

What is matter? Has a mass Takes up space

States of Matter Solid Has a rigid, definite shape The atoms, ions, or molecules that make up a solid are fixed in place

States of Matter Liquid Has an indefinite shape Is flowing matter with definite volume Takes the shape of its container Particles of a liquid can move and easily glide over each other

States of Matter Gas Has no definite shape Has no definite volume Is compressible matter Particles of gas are much farther apart and are easily pushed together

Matter Pure Substance Mixtures Compound Homogeneous Heterogeneous Uniform/Definite composition One Chemical Formula 2 or more substances physically combined Compound Homogeneous Heterogeneous Element Not uniform through out. One type of atom Found on Period Table 2 or more elements chemically combined Solutions Uniform throughout

Physical/Chemical Changes Matter/Change Physical/Chemical Changes

Physical Property Characteristics that a sample of matter exhibits WITHOUT any change to its identity.

New Substance Physical Change A change that does not produce a new substance! New Substance

Examples: Solubility Melting/Boiling Point Phase Change Size/Shape Change It’s Color (not change in) Density Electrical Conductivity Physical State (solid, Liquid, or gas)

Physical Property Extensive Intensive Depends on amount of matter present Mass Volume Intensive Does not depend on the amount of matter present Color Phase Density (mass/volume)

Chemical Property Only observed when there is a change in the composition of the substance Ability of a substance to react with other substances or to decompose.

Chemical Change A change that does produce a new substance (chemical reaction)

Physical vs. Chemical Changes “Can the change be reversed?” If yes: probably physical. If no, probably chemical. Example: Milk goes sour. Can the change be reversed? NO. You cannot get the milk to taste good again. So it is a chemical change. Note that a new substance (lactic acid) has been produced. This acid is formed when bacteria break down the lactose in the milk. Example: An ice cube melts. Can the change be reversed? YES. Just put the water back in the freezer. Note that no new substance is produced. Phase changes (changes between states of matter—solid, liquid, gas) are NOT chemical changes! This rule is not perfect; it is just meant as a guide.

Chemical Change-Look for: Formation of a gas (odor) Light produced Formation of precipitate Change in temperature (gets hot—exothermic* or cold—endothermic**) Permanent Change in color

Energy Law of Conservation of Matter Matter/Change Energy Law of Conservation of Matter

Law of Conservation of Mass (Matter) Matter can be neither created nor destroyed. Original atoms in reactants may move around, but will be found on the product side.

How many atoms of carbon are on the reactant side? Don’t need to write! How many atoms of carbon are on the reactant side? On the product side? How many H on the reactant side? How many O on the reactant side? 6 6 12 12 18 18

The mass of the reactants must equal the mass of the products!! Reactants = Products 372g = 372g

Exothermic The chemical reaction releases heat energy to the surroundings.

Endothermic The chemical reaction absorbs heat energy from the surroundings.

Energy Changes What is energy? The capacity to do work.

Two Types of Energy Potential Energy of position. Stored energy in bonds of molecules.

Example Gasoline stored at a gas station

Two types of energy Kinetic Energy in motion

Example Moving cars as they go down the road. As the gasoline is burned, energy is released from the bonds and is used to power the car’s engine.

Energy Conversions Law of Conservation of Energy Energy can be converted from one form to another, but it is not created or destroyed.

Energy can exist in these forms: Radiant: light energy sunlight Chemical: stored in bonds of molecules Fuels, food Nuclear: stored within the nucleus of atoms Electrical: Flowing electrons in a current.

Energy can exist in these forms: Mechanical: moving machine parts or body (you can think of your body as a machine too) Thermal: heat Friction causes machine parts to heat up

Thermal Energy Can be transported via 3 possible pathways

Convection The transfer of heat energy in a gas or liquid (not in solids) by movement of currents. The heat move with the fluid. Example The beach – hot air rises, cooler air from the ocean comes into replace it, and then the cool breeze cools your body.

Conduction The transfer of heat energy through matter from particle to particle. Material are actually touching! Most effective in solids, but can happen in fluids. Example Beaker on a hot plate becomes warmer because the heat from the hot plate is conducted along the beaker.

Radiation The transfer of heat energy by electromagnetic waves Example Only form that can occur in empty space without the aid of Solids, Liquids, or Gases Example Sunlight –travels through space via radiation.

What is the way that thermal energy is transported in the following? Your leg becomes warn when you place a heating pad on it. Conduction

What is the way that thermal energy is transported in the following? The pilot light in your car illuminates a map. Radiation

What is the way that thermal energy is transported in the following? Hot soup transfers heat to the air above it. Convection

The various forms of energy can be converted into one another Radiant E: Sunlight Chemical E: glucose produced in plants via photosynthesis Mechanical E: rabbit eats plant and metabolizes them to release energy for hopping.

Try this one: Trace the conversion of energy from sunlight to a person riding a bicycle. radiant E: chemical E: mechanical E: