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Physical Science
Class Notes
Ch 2. Classification of Matter/Properties of Matter/Phases of Matter
Matter: Anything that has mass and volume.
Properties of Matter
Physical Properties: Color, Shape, Size, Mass, Weight, Volume, and Density
Chemical Properties: Flammability, Oxidation, Reactivity
Substances vs. Mixtures
Substances: Matter that has a uniform and definite composition (i.e. every
sample of a substance has the same composition).
Mixtures: Matter that consists of two or more substances that are mixed together,
but are not chemically combined.
Ex’s: Sand in water, Gravel in water, Cereal, Oil and vinegar, etc.
*Mixtures can be separated manually or by using filters, magnets,
evaporation etc.
Try separating gold in a pan also containing sand.
Mixture Types (4):
1. Heterogeneous: A mixture that does not appear to be the same
throughout.
Particles are visible and easily separated
Ex: Oil/Vinegar, Orange juice and Sand/water
2. Homogeneous: A mixture that appears to be the same throughout.
Particles are not easily recognized
Ex: Milk, Sugar-water, Salt-water
3. Colloids: Homogeneous mixtures with particles that are not dissolved.
Ex: Storm-water from construction sites, smoke and paint.
4. Solutions: A mixture in which the particles are dissolved.
*Can be solid, liquid or gas
Ex: Tea, Saltwater, Sugar-Water
Related Terms:
Solute: A substance that is dissolved in a solution.
* Can be solid liquid or gas.
Solvent: A substance in a solution that dissolves another substance.
Solubility: A measure of how much solute can be dissolved in a given
amount of solution, under certain conditions.
Soluble: Able to be dissolved.
Insoluble: Unable to be dissolved.
Alloy: A metal solution.
Ex: Brass: A mixture of copper and zinc.
Suspension: A heterogeneous mixture that separates into layers over
time.
Pure Substances: Elements and Compounds
Elements: The simplest form of a pure substance.
Made up of Atoms: The basic building block of matter.
Ex: Iron (Fe), Lead (Pb), Hydrogen (H), Carbon (C)
Molecule: A neutral combination of atoms that are covalently bonded
together.
Compounds: Pure substances made up of molecules that contain more than one
kind of atom.
*Compounds can be broken down into simpler substances.
Ex: Water is a compound made up of 2 atoms of hydrogen that are
chemically bonded to 1 atom of oxygen.
Chemical Reactions
Flammability: Ability to burn in the presence of oxygen.
Reactivity: Ability to combine chemically with another substance.
http://www.youtube.com/watch?v=0QaaUw7B_js
http://www.youtube.com/watch?v=92Mfric7JUc
Recognizing Chemical Changes
Physical: A change of size, shape or phase.
Chemical: Forms a new substance.
Color Change
Ex: Steel turns orange and copper turns green
Color Change Indicators: Iodine
Production of a Gas
Ex: Baking soda/vinegar, chlorine/ammonia = Toxic: poisonous or
harmful to humans.
Formation of a Precipitate
Ex: Milk/Acid makes cheese.
Temperatures Change
Ex: Batteries getting warm
Law of Conservation of Mass: Matter cannot be created or destroyed. It can
only change forms. The mass of the products is always equal to the mass of
the reactants. During any physical or chemical change, mass is conserved.
Ch 3 States/Phases of Matter
Kinetic (Greek=to move) Theory: All particles of matter are in constant motion.
Phase Characteristics
Solid: Definite shape and volume.
Liquid: Definite volume but variable shape.
Gas: Variable volume and variable shape.
Plasma: High energy gas abundant within stars that must be contained using
magnetic fields.
Bose-Einstein Condensate (BEC): Matter cooled to near absolute zero (0 K)
with atoms behaving as single particles.
State/Phase Changes
*Changes in phase are caused by an increase or decrease in energy.
Related Terms:
Melting: Change of a solid to a liquid
Melting Point: The temperature at which a solid changes to a liquid.
Freezing Point: The temperature at which a liquid changes to a solid.
Vaporization: Change in a substance from liquid to gas.
Evaporation: Vaporization that takes place at the liquids surface.
Boiling: Process by which the particles inside a liquid as well as on the
surface of a liquid change to gas.
Boiling Point: Temperature at which a liquid boils.
* The lower the air pressure, the easier it is for the particles to travel
up through the liquid and leave as a gas.
*As air pressure decreases, such as with increased altitude, the boiling
point decreases.
Condensation: Change of a gas to the liquid phase.
Sublimation: When the particles on the surface of a solid change directly to
the gas phase.
Ex: Dry ice
Deposition: When a gas goes directly to the solid phase without forming a
liquid.
Behavior of Gases
Boyle’s Law: The volume of a fixed amount of gas varies inversely with the
pressure of the gas (i.e. as one increases, the other decreases).
Ex: If you push down on the handle of a bicycle pump, you decrease the
volume of the cylinder, and you increase the pressure of the gas inside.
P1V1= P2V2
Charles’s Law: The pressure and/or volume of a fixed amount of gas varies
directly with the temperature.
Ex: Basketballs get flat when they are cold.
V1 = V2
T1
T2
*Together, Boyle’s Law and Charles’ Law are referred to as the Gas Laws
and they describe the behavior of gas with regard to: volume,
temperature, and pressure.
P1V1
T1
= P2V2
T2
Discuss phet simulator for phases of mater
Heat and Phase Changes
*Energy is either absorbed or released during phase changes.
Heat of Vaporization: The amount of energy that must be absorbed when a
substance changes from a liquid to a gas.
Ex: Boiling water on a stove at different altitudes
Heat of Fusion: The amount of energy that must be absorbed when a
substance changes from liquid to a solid.
Ex: Using ice to protect crops.
Exothermic: Phase changes and chemical reactions that involve a release of
energy.
Endothermic: Phase changes and chemical reactions that involve absorption
of energy.