Classification of Matter. Scientists like to classify things Scientists classify matter by its composition All matter can be classified as a substance.
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Classification of Matter
Classification of Matter
• Scientists like to classify things
• Scientists classify matter by its composition
• All matter can be classified as a substance or mixture
Why isn’t it a good idea to classify matter by its phases?
• Because one kind of substance can exist in more than one phase – such as H20.
Why isn’t matter classified according to physical characteristics such as
color?
Scientists wouldn’t find it very useful to group gold, sunflowers, and the sun together.
Classification of Matter
• Matter– All matter has properties– Properties are used to
classify matter– ALL matter is made of a
pure substance or mixture of substances
Substances• Substance– Type of matter with a
fixed composition– All substances are
built from atoms• Atoms are the smallest
part of matter
– 2 types of substances1.Elements2.Compounds
Elements
• Elements– Consists of only one type
of atom– Can’t be broken down
into simpler substances– Chemists use symbols to
recognize elements– These are found on the
periodic table of elements
Elements
• Elements– Examples
• Oxygen• Carbon• Hydrogen• Iron• Neon• Copper• Nitrogen• Mercury
Compounds
• Compounds– Two or more elements
combined– Fixed proportion– Can’t be broken down by
physical means . . . only chemically
Compounds
• Compounds– Examples
• Water (H₂O)• Salt (NaCl)• Carbon Dioxide (CO₂)• Carbon Monoxide (CO)• Glucose (C₆H₁₂O₆)
Mixtures
• Mixtures– Made up of two or more
substances– CAN be separated by
physical means– 4 types of mixtures
• Homogenous• Heterogenous• Colloids• Suspensions
Homogenous Mixtures
• Homogenous– Contains two or more
substances blended evenly throughout
– Also called solutions– Characteristics:
• Blended evenly• Particles will not settle• Can’t see individual
particles within the solution
• “Well mixed”
Homogenous Mixtures
• Homogenous Mixtures– Examples
• Gatorade• Bottled Soft drinks• Kool-Aid (well mixed)• Vinegar• Brewed coffee
Heterogenous Mixture
• Heterogenous Mixture– Materials can be easily
distinguished– Characteristics
• Not mixed evenly• Some can be hard to
detect• Most substances are
heterogenous
Heterogenous Mixture
• Heterogenous Mixtures– Examples
• Pizza• Chicken noodle soup• Concrete• Dirt/Soil• Cereal• Drinks with ice
Colloids
• Colloid– Special kind of mixture– Has both homogenous
and hererogenous qualities
– Characteristics• Particles are suspended
but won’t settle• Particles are bigger than
those in solutions• Will produce tyndall
effect (scattering of light)
• Examples– Milk– Fog– Paint
Colloids• Tyndall Effect
Suspensions
• Suspensions– Heterogenous mixture– Characteristics
• Particles big enough to see
• Particles will settle to bottom
– Examples• Muddy water• Italian salad dressing
Suspensions
Characteristics of Mixtures
Properties of Matter; Physical and Chemical
• Physical Properties– Characteristic of a
material you can observe
– Examples:• Color• Size• Shape• Density• Melting point• Boiling point
Physical Properties
• Physical Property– Appearances of matter
are physical properties– Appearance:
• Shape• Color• State of matter (solid,
liquid or gas)• Odor• Mass• Volume
• What are some physical properties of the liquid in the image below?
Physical Properties
• Physical Properties– Behavior of matter are
also physical properties– Behaviors
• Magnetic• Malleable (stretch or
bend)• Ductile (drawn into wire)• Ability to flow easily (soft
drink versus syrup)
Physical Change
• Physical Change– A change in size, shape
or state of matter– The identity of the
material doesn’t change– Examples
• Tearing a piece of paper• Breaking glass• Painting a wall• Liquid freezing• Solids melting
Chemical Property
• Chemical Property– Characteristics that
indicate whether it can undergo a chemical change
– Examples• Flammability• Certain medicines reacting
to light
Chemical Changes
• Chemical Changes– A change from one
substance to another– A new substance has
formed – Can’t reverse effects– Examples
• Cooking an egg• Rust• Burning• Rotting food
• Physical or Chemical Change?
• Physical Or Chemical Change?
Separating Mixtures
• Can use physical properties to separate mixtures into its components
• Distillation– Uses boiling point to
separate components of liquids
Law of Conservation of Mass
• Law of Conservation of Mass– During a chemical
change, matter is not created or destroyed
– Mass before chemical change equals mass after chemical change
Video Clips for Review
• Physical and Chemical Properties
• Chemical Versus Physical Changes
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