Classification of Matter

Matter

Matter: Anything that has mass and volume

3 phases of matter

The Nature of MatterThe Nature of Matter

Chemists are interested in the nature of matter and how this is related to its atoms and molecules.

Gold Mercury

Chemistry & Matter

• We can explore the MACROSCOPIC world — what we can see —

• to understand the PARTICULATE worlds we cannot see.

• We write SYMBOLS to describe these worlds.

A Chemist’s View of Water

H2O (gas, liquid, solid)

MacroscopicMacroscopic

SymbolicSymbolicParticulateParticulate

A Chemist’s View

2 H2(g) + O2 (g) --> 2 H2O(g)

MacroscopicMacroscopic

SymbolicSymbolicParticulateParticulate

Kinetic Nature of MatterKinetic Nature of MatterMatter consists of

atoms and molecules in motion.

STATES OF MATTERSTATES OF MATTER

• Solids — have rigid shape, fixed volume. External shape can reflect the atomic and molecular arrangement.

• Liquids — have no fixed shape and may not fill a container completely.

• Gases — expand to fill their container.

OTHER STATES OF MATTEROTHER STATES OF MATTER

• PLASMA — an electrically charged gas; Example: the sun or any other star

• BOSE-EINSTEIN CONDENSATE — a condensate that forms near absolute zero that has superconductive properties; Example: supercooled Rb gas

Physical Properties– Characteristic of a substance that can be

observed (using your senses) without changing the substance into something else.

Physical properties are used to identify, describe and classify matter.

Hardness Texture Color

Odor Taste Temperature

More EXAMPLES - Physical

• size, shape, freezing point, boiling point, melting point, magnetism, viscosity, density, luster and many more.– Viscosity - The resistance of a liquid to

flowing.– Examples:– Low viscosity-water, rubbing alcohol– High viscosity-honey

Physical Changes– can be observed

without changing the identity of the substance

Some physical changes would be

• boiling of a liquid• melting of a solid• dissolving a solid in a liquid

to give a homogeneous mixture — a SOLUTION.

Chemical Properties

• Chemical properties are characteristics involved when a substance interacts with another substance to change its chemical make-up.

Flammability Rusting Creating gas bubbles

Creating a new chemical

product

Reactivity with water

pH

Chemical Change

• Chemical change or chemical reaction — transformation of one or more atoms or molecules into one or more different molecules.

• Burning hydrogen (H2) in oxygen (O2) gives H2O.

Classification of Matter

• Now that we have defined chemical and physical properties of matter, we can use that to help us classify it.

• One way chemists classify matter is based on its purity.

Matter

Mixture Pure Substance

ElementCompoundHeterogeneous Mixture

Homogeneous Mixture

Can be separated physically

Cannot be separated physically

Can see the parts

Cannot see the parts

Can be separated chemically

Cannot be separated

Most impure Most pure

suspension colloid

Suspension

• Heterogenous mixture containing solid particles that are sufficiently large for sedimentation (or settling).

• Example: sand in water

Colloid

• A colloid is a substance microscopically dispersed throughout another substance.

• Dispersed particles are very small and have a diameter of between approximately 2 and 500 nanometers.

• Example: homogenized milk

Classification of Matter

• Pure Substance – Matter that has only 1 set of chemical and physical properties.

Example: Pure water always has the exact same chemical and physical properties under the same conditions.

If water ever tastes different then it isn’t pure water; it fits into our next category.

Classification of Matter

• Mixture – Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties.

Example: Copper and Zinc can be mixed together to produce brass.Even though it may look different, it is still copper and zinc. Each metal retains its own properties like melting point.

Classification of Matter

• Mixture – Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties.

Unlike pure substances, mixtures can always be separated by physical means.

How could we separate the copper and zinc back out?

Mixtures

• Mixture – Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties.

If a sample of sand contains iron and salt, how could you separate them from the other minerals?

Pure Substances

• Pure substances can also be divided into 2 categories: compounds and elements.

Pure Substances

• Compound – Two or more elements chemically bonded together.

Examples:Carbon Dioxide (CO2)Water (H2O)Salt (NaCl)Sucrose (C12H22O11)

Pure Substances

• Compounds have only 1 set of properties. They cannot be separated by any physical process.- Can only be separated by a chemical reaction.

Water can be separated into Hydrogen and Oxygen by a process called Electrolysis.

Pure Substances

• Elements – Substances made up of only one type of atom. - Cannot be separated by any physical OR chemical process.

Examples:CarbonHeliumGold

Classify the following slide using these five classifications:

- Non-matter- Heterogeneous Mixture- Homogeneous Mixture

- Compound- Element

HeliumHe Bronze

Cu + Sn

Electricity

SteelFe + C

WaterH2O

Cookie

AirN2 + O2 + Ar + CO2

Carbon DioxideCO2

Italian Dressing

IronFe

Salt WaterH2O + NaCl

DiamondC

Heat

Light

MercuryHg

RAFT• Role: Forum/Blog poster. You can be either a

“Troll” or a model poster. Create screen name and avatar.

• Audience: Readers in the forum “Safety in the Chemistry Classroom.

• Format: Internet Forum Post• Topic: Respond to Free4All’s post: “I don’t see

why my teacher is always on me about my goggles. They are MY eyes! Such a pain”