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