States of Matter

What is Matter? Anything that has mass and occupies space I.Types A.Solids: 1.rigid structure 2.fixed composition 3.particles vibrate in place because of very strong attraction between particles 4.Definite volume & shape

A. Liquids: 1.particles flow or slip past each other; 2.definite volume; no definite shape and takes shape of container; 3. have more Kinetic (energy in motion) Energy than solids; viscosity (resistance to flow)

A.Gases: I.Particles are random II.Have the most KE III.No definite volume or shape IV.Fill their container – diffusion V.Exerts pressure in all directions

D.Plasma 1.High energy due to atoms having electrons stripped off 2.Matter consisting of positively and negatively charged particles. 3. Ionized gas characterized by its temperature, density, and conductivity. 4.Examples: fire, lightning, stars, and neon signs **What extra credit? Find the meaning of the word plasma as it is used by biologists and compare to the meaning which physicists use. Write it up and turn it in by Tuesday, October 11, 2011.

Kinetic Theory 1. All matter is made up tiny particles called atoms 2. These particles are always in motion. If you increase the temperature, the particles will move faster. 3. At the same temperature, more massive particles will move slower.

Energy’s Role The phase of matter is determined by the physical condition of that matter. When there is a change in state of matter, the composition of the matter does NOT change. Two physical conditions of primary importance are temperature and pressure. Increased temperature causes particles to move faster (increasing KE).

Energy’s Role (cont.) Freezing point Melting point Condensation point Boiling point Sublimation – evaporation of a solid directly to a gas without becoming a liquid Deposition – type of condensation where a gas becomes a solid without going thru the liquid phase CW: Interpret diagram: S →L→G

Thermal Expansion Increased temperature causes matter to expand. Example: concrete and concrete expansion joints on I-20. Exception to this rule is water. Water expands when it freezes because the molecules begin to form a crystalline structure with air pockets. This is why ice floats.

Temperature vs. Thermal Energy Temperature –Average KE –Does not depend on the amount (size or volume) of a substance Thermal Energy –Total amount of energy –Depends on amount of substance

Energy and Changes of State The identity of a substance does not change during a change of state, BUT energy does. Where does the energy come from to cause a phase change? Endothermic vs. Exothermic Which phase changes are endothermic and which ones are exothermic?

Class Work Create a comparison table for the 5 changes of state. Include information about the states of matter and the direction of energy transfer. Illustrate phase changes pg. 87 Melting and freezing point have the same temperature. Then what determines if a solid is becoming a liquid or if a liquid is becoming a solid?

Laws of Conservation of Mass and Energy Energy and mass are not created or destroyed. Energy and mass are either transferred or transformed. During a phase change, the mass of the object remains constant. Energy moves in or out.

Physical Properties Liquids and gases are called fluids. Fluids are matter that flow. Physical properties remain the same for a pure substances. Can be measured and observed without a change in composition. Remain constant for specific pure substances Use physical properties to help us select usefulness of a substance.

Physical properties (cont.) A. Buoyancy 1.Ability of a fluid to exert an upward force on an object immersed in it. 2.If buoyant force is equal to object’s weight, then it floats. How can you make a solid object that sinks to float ?

Buoyancy Lab 1. Take a lump of modeling clay. Place it on the water. Does it float? 2. Re-shape the clay to be able to hole an object. Place the re-shaped clay on the water. Does it float? Re-shape until it does. 3. Illustrate the shape of your boat. 4. With the boat floating on the water, place marbles one by one in it until the boat sinks. Record the number of marbles. 5. Create a chart of the class data. 6. Draw a conclusion based on this lab. –How did shape effect buoyancy? –Predict what would happen if the clay was placed in syrup instead of water before and after the clay lump was shaped. –Compare your prediction to this lab.

Physical Properties (cont.) B. Density 1. mass per unit volume d = m/v 2. units are g/cm^3 or g/mL 3. The atomic mass of an element and amount of space between particles determines density.

Physical Properties (cont) 4. Density Rules to follow: a.The amount of substance does NOT affect density. b.Temperature affects density. Objects will become less dense as temperature increases due to thermal expansion. c.Pressure affects density of gases and plasmas, ( but not solids or liquids.

Density Calculations 1.How is density calculated? 2.A sealed 2500 cubic centimeter flask is full to capacity with 0.36 g of a substance. Determine the density of the substance. Guess if the substance is a solid, liquid, or gas. 3.A piece of metal has a volume of 6.7 cubic centimeters and a mass of 75.7 g. Find the metal’s density. 4.What is the volume of 325 g of metal with a density of 9.0 grams per cubic centimeters?

Density cont. Density is mass per unit volume. Most of the volumes so far we have assumed are solid cubes and liquids in graduated cylinders. How can the density of a rock with an irregular shape be measured?

Physical Properties (cont) C. Pressure 1. force exerted per unit area 2. applied to a fluid is transmitted throughout the fluid (Pascal’s Principle) example: when you squeeze one end of a toothpaste tube; hydraulics 3. SI units: pascals (Pa) 4. Calculate by using P1V1 = P2V2

Gas laws: pressure, temperature, volume Bernoulli’s Principle: buoyancy Boyles’ Law: relates pressure to volume Charles’ Law: relates pressure to temperature. Combined gas law: relates pressure, temperature and volume Create and use a PTV tool

Other physical properties Melting point Boiling point Freezing point Shape Color Odor Texture Conductivity Magnetism

Questions to Consider How does the kinetic theory help us to understand the phases of matter? What is the relationship between temperature and kinetic energy? How does temperature affect the density of an object?