Matter: Physical vs. Chemical
Properties of Matter• Characteristics that enable us to
distinguish one kind of matter from another.
• How can we distinguish hydrochloric acid from water?
Types of Properties• Extensive
– Depends on the amount of matter – e.g., volume, mass, amount of energy
(cal)• Intensive
– Does not depend on the amount of matter
– e.g., melting point, boiling point, density, conductivity
Physical & Chemical Properties
• Physical Property–Can be observed or measured
without changing a substance’s composition.
Boiling Point
Density
Melting Point
MalleabilityConductivity
Color
HardnessMagnetism
Ability to transmit light
Physical & Chemical Properties
• Chemical Property–Can only be observed by
changing the composition of the material
–Changes its identity
The ability of a substance to…Rust
DecayBurn
React with acid, base, or water
Ferment
Properties of Water• Water expands as it freezes.
(Physical)• Hydrogen peroxide, H2O2 can decompose to
produce water. (Chemical)
• Water boils quicker in Denver, CO than at the beach. (Physical)
• When an electrical current is passed through water, elemental hydrogen and oxygen are produced. (Chemical)
• Salt can dissolve in water. (Physical)
Physical & Chemical Changes
• Physical Change–Will change the visible
appearance, without changing the composition of the material
–Changes that effect only physical properties.
–Does not change the composition!
Physical Changes
• Boil• Melt• Freeze• Distillation• Sublimatio
n• Expand
• Crush• Diffuse• Condens
e• Osmosis• Cut• Split• Crack
Physical & Chemical Changes
• Chemical Change–Changes that involve a
change in the composition of the substance.
–New matter is formed
Chemical Changes• Ferment• Decay/Decompose• React with acid, base, or water
• Neutralize• Rust• Digest• Tarnish• Explode / Burn• Ignite• Cook
2H2O 2H2 + O2
• Reactants the stuff you start with
• Products- what you make
• Arrow points from the reactants to the new products• The products will have NEW
PROPERTIES different from the reactants you started with
Indicators of Chemical Change
1. Color Change2. Gas produced 3. Temperature
change4. Light produced5. Precipitate forms6. Irreversibility
– Not easily reversed!
• Color Change–Very hard to reverse–Think about cooking an
egg
Indicators of Chemical Change
• Gas produced– Bubbles are produced– Careful there are
examples of bubbles that are not chemical – boiling water bubbles• Physical change Water
vapor starts to form inside the liquid in the form of bubbles
Indicators of Chemical Change
• Temperature change–Heat given off- Exothermic
• Feels hot• Feel someone after they workout
they’re hot–Heat absorbed- Endothermic
• Feels cool• Sweating while working out
Indicators of Chemical Change
• Light produced–Striking a match flame
produced–Fireworks
Indicators of Chemical Change
• Precipitate forms– 2 liquids
solid + liquid
Indicators of Chemical Change
Law of Conservation of Matter
• In any physical or chemical change, matter is neither created nor destroyed.
• During any chemical reaction, the mass of the products is always equal to the mass of the reactants
• All the mass can be accounted for!!– Burning of wood results in products
that appear to have less mass as ashes.
– Where is the rest??
Law of Conservation of Matter