Download FHN - Chemical and Physical Changes

Physical Property
 A property that can be observed without changing the
composition of a substance
 Viscosity
 Conductivity
 Malleability
 Hardness
 Melting and Boiling Points
 Density
Chemical Property
 A change that can only be observed when the
substances in a sample of matter are changing into
different substances
 Flammability
 Reactivity
Physical Change
 A physical change is when the properties of the material
change, but the substances in the material stay the same.
 Change in state
 Solid melting to a liquid
 Liquid evaporating to a gas
 Gas condensing to a liquid
 Liquid freezing into a solid
 Usually occur with a change in temperature
 Can also be when a substance dissolves in a liquid, but does
not change its chemical make-up.

When sugar dissolves in water, the sugar is still sugar, just
surrounded by water particles.
 Can also be a change in shape.
 These changes can usually be easily undone.
Filtration
 A physical change
 Separating one substance from another.
 Uses the difference in the size of the substance
Distillation
 Separates substances
based on differences in
the physical properties of
two of more substances.
Chemical Change
 A change that occurs when a substance reacts and
forms one or more new substances.
 A substance changes chemically.
 New products are formed



A nail rust in the outdoors
Food is burned on a stove top
Acid is mixed with a base to neutralize the two.
 Usually cannot be easily undone.
 Identified by changes in color, formation of gas or
precipitate.
Physical v. Chemical Changes
 Physical changes are: _____________________
 Examples:
 1.
 2.
 3.
 Chemical Changes are: _________________
 Examples:
 1.
 2.
 3.
Whiteboarding
 Salt is mixed with water
 Physical
 Coal is burned
 Chemical
 A Sweet Tart is crush into powder
 Physical
 A copper roof turns green
 Chemical
 Alka-Seltzer is mixed with water.
 Chemical
 Bread grows mold
 Chemical
 A bicycle chain breaks
 Physical
 A bicycle chain rust
 Chemical
States of Matter
 Solid
 Definite volume, definite shape
 Liquid
 Definite volume, indefinite shape
 Gas
 Indefinite volume, indefinite shape
Systems
 Open System
 System may exchange mass and
molecules with the
surroundings
 Closed System
 System is cut-off from
surroundings, no mass or
molecules can enter or exit.
Conservation of Mass
 Not matter what happens in a chemical or physical
change in a closed system, the amount of mass that
exist before the change must be exactly the same after
the change has happened.
 15 grams of water is evaporated, how much
water vapor is produced?