Physical Science Chapter 9 Classification of Matter
Physical Properties of Matter
-property – characteristic of a substance that describes an object
-physical property – characteristic of matter that can be observed without changing it
-color, shape, density, hardness, boiling/freezing pt, odor, etc.
-does not involve a change to something new
-chemical property- characteristic that determines how substance reacts to form other
substances
-involves a change to something new
-corrosion – destruction of metal because it combines chemically with other substances
Changes in Matter
-all changes involve an energy change
- Law of Conservation of Matter- matter cannot be gained or lost during a chemical change
-physical changes- a change in the size, shape, color, or state of matter (solid, liquid, ice)
-it only changes it’s appearance, not the actual substance
-chemical changes – change in a substance that produces a NEW substance with different
Properties (ALL CHEMICAL CHANGES ALSO PRODUCE PHYSICAL CHANGES)
-electrolysis: a chemical change produced by an electrical current
-electricity can separate the hydrogen and oxygen in water
-‘lysis’ means to break down
-clues that a chemical change has occurred :
-heat or light given off
-bubbles produced
-sound given off
-odor is produced
Composition of Matter
Matter- anything that has mass & takes up space
Pure substance: Matter in which all the particles are alike
-only 2 substances in science are:
1. Elements
2. Compounds
Element = matter that has only 1 type of atom (atoms make up elements)
Atoms= Building blocks of all matter – smallest part of element
-chemical symbols – representation for elements
- 1 or 2 letters; 1 st capitalized, 2 nd isn’t = Ca
-some symbols are for the Latin name - Au = Aurum (gold)
- elements are found on the Periodic Table

Compound – matter made of 2 or more elements chemically joined together, ALWAYS IN THE SAME
RATIO
-water is ALWAYS H
2
O, not H
2
O
2
or H
2
- molecules = made up of 2 or more atoms chemically combined
- smallest part of a compound
O
3
- water always has 2 Hydrogen and 1 oxygen
Mixtures – 2 or more elements or compounds that are blended, not chemically combined
-each part keeps its own properties
-can be combined in ANY ratio – 1 cup sand and 1 gallon salt or vice versa – doesn’t matter
-2 types
-Heterogeneous mixture: substances are not spread evenly throughout mixture
- pizza, chocolate that settles in bottom of cup, city air (smog particles),paint- oil
floats on top and has to be mixed in,
-Homogeneous mixture: substance are spread evenly throughout the mixture
-milk, pure water, flat pop, any element or compound
Differences between Compounds & Mixtures
Compounds
1.
Elements combined in certain ratio (H
2.
Elements chemically combined
2
O)
Mixtures__________________________
Parts can be combined in any ratio
Parts physically combined
3.
Compound has different properties from its elements Parts keep their own properties
Solutions, Suspension & Colloids
Solution: Homogeneous mixtures made of more than 1 substance –don’t settle or scatter light
2 parts:
1. solvent = substance DOING the dissolving
2. solute = substance BEING dissolved
-soluble: means it CAN be dissolved like salt in water
-insoluble: means it CAN’T be dissolve like oil in water or metal in water
Alloy = a solution made of metals that improves its properties, or produces a desired property
-
Many uses in automotive, aerospace, construction, medical, manufacturing areas
-
Bronze was the first alloy discovered – made of copper and tin
-
Brass – alloy made of copper & zinc
-
Steel – alloy made of iron and carbon (pure carbon = diamond)
-
Types of alloys
-Aluminum alloys – strong and lightweight
-Copper alloys – excellent thermal and electrical performance
-Nickel alloys- good corrosion and thermal resistance
-Titanium alloys= very strong, tough and corrosion resistant
-stainless steel alloys-very corrosion resistant

Suspensions
-
HETEROgeneous mixture in which particles are large enough to be seen
-
Gravity makes ‘suspended’ particles settle
-
Can separate parts using filter paper
Colloids
-
Mixtures with particles larger than solution, but smaller than suspension
-
Does NOT settle
-
Scatters light – cloudy looking
-Tyndall effect – ability of a colloid to scatter light
-beam of light in smoke, dust
-beams of light coming off street lights in winter on icy nights
-Brownian motion- Random motion of particles in a colloid
-dust particles swirling around (seen in sunlight beams)
-coagulation – the clumping together of particles
-destroys colloids – particles stick together and unable to stay suspended
-emulsifier- substance that allows colloids to stay mixed – egg keeps oil/water mixed in mayo
Types of Colloids
1. Foam – whipped cream, soap suds, marshmallow
2. Aerosol = fog, clouds
3. Emulsion = milk, mayo, cheese
4. Smoke = particles in air
5. Sol = jelly, pearls