Matter

What is matter? Has mass Like a rock is an idea matter? Takes up space Like air or water is heat matter?

Matter Pure substance Can it be physically separated mixture yes no no Can be chemically separated Uniform composition? Homogeneous mixture Heterogeneous mixture compound element

Physical separation methods Filtration – process that separates materials based on size Distillation – process that separates substances in solution based on their boiling points Chromatography -

Mixtures Homogeneous: evenly mixed cannot see individual parts solution example: salt water Heterogeneous: can see individual parts example: granite rock

Solution Systems gas-gas: Air Gas-liquid: Soft drink Liquid-gas Moist air Liquid –liquid Vinegar Solid-solid Steel (an alloy)

Pure Substances Examples: table salt (NaCl) Elements: Composed of identical atoms Examples – copper, hydrogen Compounds: Composed of 2 or more elements in a fixed ratio Has different properties than constituent elements Examples: table salt (NaCl) http://www.youtube.com/watch?v=Mx5JJWI2aaw

Changes in state of matter sublimation melting vaporization solid liquid gas freezing condensation deposition

Solids have a definite shape and a definite volume. Liquids have and indefinite shape and a definite volume. Gases have a indefinite shape and an indefinite volume.

Particle movement and phase solid liquid gas

Particle movement and phase Add heat Add heat solid liquid gas

Physical Properties Can be observed or measured without changing the composition of the matter Melting point, boiling point Density Solubility Color Malleable/ductile Hardness Conductivity Viscosity Odor

Physical Changes Changes of state: melting, freezing, condensation, etc… Drawing copper into a wire Desalinization The substance only changes size, shape or state – it does not become a different substance

Chemical Properties The ability of a substance to combine with or change into another substance Reactivity flammability A new substance is formed

Chemical Changes Combustion Rusting, tarnishing

Evidence of a chemical change Color change Production of a gas Formation of a precipitate (a solid that forms and separates from a liquid) Temperature change

Check for understanding indicate if the change is physical or chemical Melting ice Painting wood Burning wood baking Breaking glass Burning propane Iron rusting

Temperature The average kinetic energy of the particles in an object Absolute zero – no particle movement; theoretically impossible Regardless of how cold an object is the particles that make up that object are moving. The warmer an object is the more the particles move; the cooler – the slower

Phase change diagram

Phase Change Diagram Triple point – the point that represents the temperature and pressure at which all three states can coexist Lines between phases – water can exist in both phases Critical point – the temperature and pressure above which water cannot exist as a liquid

Changes in state of matter sublimation melting vaporization solid liquid gas freezing condensation deposition

Vapor pressure is the pressure exerted by a vapor over a liquid The temperature at which the vapor pressure of a liquid equals the atmospheric pressure is the boiling point of that liquid Vapor pressure and boiling (11) vapor pressure and boiling Boiling on Everest

Heating/cooling curve

Heating curve Diagonal lines are temperature ranges at which the substance exist as a solid, liquid or gas. The horizontal lines are temperatures at which the substance is melting or boiling. During a phase change the temperature of the substance is not changing.

q = mcDT – formula for calculating heat q – heat absorbed or released m - mass of substance c – specific heat (the heat required to raise the temperature on one gram of a substance by one degree Celsius) DT – change in or difference in heat The unit for heat is the joule (J)

Heat of Fusion/heat of Vaporization Heat of fusion – q = Hf is used to calculate heat absorbed or released during melting or freezing Heat of vaporization – Hv is used to calculate heat absorbed or released during vaporization or condensation

One joule = 0.2390 calories In the metric system the amount of heat required to raise the temperature of one gram of pure water by one degree Celsius = one calorie