Matter – A Review

• Has mass• Takes up space

ex….

• Chemistry is the study of MATTER!

Topic 4.D - Classifying

Unit 1 – Organizing Matter – 2011

Classifications of Matter

Homogeneous MixtureSame throughout

Heterogeneous MixtureVaries in content

MixturesContain more thanone kind of matter

ElementAll atoms are the same

CompoundConsists of two or more

types of atoms

SubstancesCannot be separated into differentkinds of matter by physical means

MatterAnything that has mass and takes up space

Mixtures

• Contain more than one kind of matter• Can be separated physically

a. Sortingb. Filteringc. Heating and cooling

Types of Mixtures

a. Homogeneous mixtures – are the same throughout; every sample has the same ratio of ingredientsEx: milk

b. Heterogeneous Mixtures – vary throughout; each sample has the may have a different ratio from the nextEx: chicken soup

Mixture Examples

• Petroleum (Crude Oil) – 1,000,000 molecular compounds

• Soda – Carbonated water, corn syrup, caramel color, phosphoric acid, natural flavors and caffeine

• Paint – Pigment, Latex, thinning agents

Pure Substances

Cannot be separated by physical means May contain more than one kind of

matter held together by chemical bond examples: Lithium, NaCl

Types of Substances

a. Elements – Contain only one kind of matter; (one kind of atom)

b. Compounds – contain two or more elements; can be separated chemically

Topic 4.B - Properties of Matter Unit 1 – Organizing Matter - 2011

Intensive vs. Extensive

• Intensive properties: characteristics that do not depend on the amount of matter present.– example: density

• Extensive properties: characteristics that depend on how MUCH matter is present– example: mass

Intensive Properties

• Properties that do not change depending on how much stuff you have.

• These are observable whether you have a lot or a little of it.

• For example, a diamond will be sparkly and lustrous no matter if it is tiny or giant.

Extensive Properties

• Properties that change depending on how much stuff you have.

• These will change if you have a small amount or if you have a large amount.

• For example, a small sample of sand will have less mass than a large sample of sand.

Types of Physical Properties

• Something you can observe or measure without changing the matter into something else.

• For example, you can measure how much something weighs or what it smells like without changing it into something else.

• You cannot tell if something will burn without changing it into something else.

1. Density

how tightly packed the particles are in a substance (“compactness”)

The relationship of mass to volume

Intensive or extensive?

1. Density (contd.)

• Less dense = float• More dense = sink• example: substances

that are less dense than water will float on water.

2. Viscosity

resistance to flow Viscous fluids are thick and hard to pour Large molecules flow more slowly (MORE

VISCOUS) Small, smooth molecules flow

more quickly (LESS VISCOUS)

Intensive or extensive?

3. Malleability A solid’s ability to be

pounded into thin sheets

4. Ductility the ability to be made into

wire

Intensive or extensive?

Intensive or extensive?

5. Conductivity

• The ability of a material to conduct electricity, heat, or sound

Intensive or extensive?

6. Melting Point

• temperature at which a solid melts to beomea liquid

• temperature at which a liquid boils to become a gas

7. Boiling Point

Intensive or extensive?

Intensive or extensive?

8. Luster

• how much the surface of a material reflects light (“shine”)

• example: chrome

Intensive or extensive?

9. Solubility• the ability of one substance to

be dissolved in another substance

• solubility can depend on temperature, pressure, and how much of each substance is interacting

Intensive or extensive?

Types of Chemical Properties

• The ability of something to react with something else or to change into something else.

• You cannot observe chemical properties without changing the object into something else.

• For example, if you observe that a nail will rust, it has already changed into rust.

Reactivity

Copper Reacts with Nitric AcidMagnesium Reacts with

Hydrochloric Acid

Describes how readily a substance will undergo a chemical reaction with another substance

Toxicity

• The degree to which a substance can damage an organism

Corrosiveness

• A measure of how much a substance can destroy or irreversibly damage another surface or substance with which it comes into contact.

Often strong acids and bases.

Flammability

• How easily something will burn or ignite

Topic 4.A - Changes in Matter

Unit 1 – Organizing Matter - 2011

Physical vs. Chemical

• Physical change - same substance before and after

• Chemical Change – make a new substance

Physical Changes

• Affect only physical properties: – size– shape– state

Examples of Physical Changes

• Shattering glass• Crushing ice• Letting ice melt• Compressing a gas• dissolving

Phases or states are: solid, liquid, gas (and plasma)

changes from one state of matter to another

based on the addition of or loss of energy (heat or thermal energy)

Phase Changes (a.k.a. “changes of state)

Phase Changes (a.k.a. “changes of state)

• Melting: solid to liquid• Boiling or Evaporation: liquid to gas• Condensation: gas to liquid• Freezing: liquid to solid• Sublimation = solid straight to gas!

Chemical Changes

• The result of chemical reactions• Bonds must be broken and/or created to form

a new substance(s)

How do you know if a chemical change has occurred?

• Product is obviously different than starting materials

• Energy has been released or absorbed (careful – did you add the energy?)

• Obvious changes in:– Color– Texture– Opaqueness– Gas bubbles form (not boiling!)

Topic 4.C – Phases of Matter

Unit 1 – Organizing Matter - 2011

Phases of Matter

gas liquid solid• most movement (high kinetic energy)•shape and size is dependent on the container a liquid is in• “Fluids”•Molecules can be compressed closer together• least dense phase

•shape and size is dependent on the container a liquid is in•“Fluids”• molecules are touching, but “slide” around each other

• molecules are touching and vibrate in place•solids have a definite shape and size