Physical and Chemical Properties and Changes
Physical Property
 Definition: a characteristic of a substance that can be observed without
changing it into another substance
 Examples: color and texture, flexibility, freezing point, state of matter,
luster, ability to conduct heat and electricity, attracted to a magnet, etc.
 Identify some physical properties of silly putty
Chemical Property
 Definition: a characteristic of a substance that describes its ability to change
into different substances
 To observe chemical properties of a substance, you must try to change it to
another substance
 Examples: flammability, ability to react with oxygen (rust vs. gold), ability to
react with sulfur (silver tarnishing vs. gold)
 Identify some chemical properties of a match
Physical Change
 Definition: any change that alters the form or appearance of matter but
does not make any substances in the matter into a different substance
 A substance that undergoes a physical change is still the same substance
after the change.
 Examples: changes of state, dissolving, bending, crushing, breaking,
chopping, filtration, distillation
 Identify the physical change with the lava lamp and dissolving sugar (point
out physical properties that are the basis for the changes)
Chemical Change
 Definition: any change in matter that produces one or more new
substances
 Aka: chemical reaction
 A chemical change produces new substances with properties different from
those of the original substances
 Examples: hydrogen peroxide into water and oxygen, rusting, burning
methane, combustion, electrolysis, oxidation, tarnishing
 Define flammability and reactivity
 Identify the chemical change in the alka seltzer cannon and methane
mamba (point out properties of original versus new substances)
Conservation of Mass
 Matter is not created or destroyed in any chemical or physical change
 Aka: Law of Conservation of Matter
 Example: Methane + Oxygen  Carbon dioxide and water
Matter and Thermal Energy
 Any time there is change, energy is involved
 Temperature: the average kinetic energy of the particles in a substance
 Thermal energy: the total PE and KE of the particles in a substance
 Endothermic: energy in, a change in which energy is taken in, ex: melting
 Exothermic: energy out, a change in which energy is released, ex:
combustion