Chemistry W2: What is Matter? (copy)

MATTER

Anything that has mass and volume. Includes atoms and anything made up of atoms, but not other energy phenomena or waves like light or sound.

a physical substance of which systems may be composed.

Macroscopic

Objects/phenomena are large enough to be visible practically with the naked eye, without magnifying optical instruments.

Microscopic

Objects and events are smaller than those that can easily be seen by the naked eye, requiring a lens or microscope to see them clearly.

Atoms

Make up everyday objects, consisting of interacting subatomic particles like protons and neutrons.

Tiny building blocks of matter.

liquid oxygen

(gas compressed such that it turned liquid)

Mass

the measure of the amount of matter in something. not a substance but a quantitative property of matter and other substances or systems.

Air (and all other gases)

invisible to the eye, have very small masses compared to equal volumes of solids and liquids, and are quite easy to compress (change volume).

mass of air

approximately 0.0002 pounds or 0.09 grams

Intermolecular Forces (IMF)

Force that causes molecules to move together

MOLECULES

The most important method that nature uses to organize atoms into matter are groups of two or more atoms that have been bonded together.

It has its own set of chemical properties, and it’s these properties with which chemists are most concerned

Physical States of Matter

• State that a given substance exhibits is also a physical property

• The physical state of everything depends on the temperature 

• All substances can be any state of matter

Solid

• Definite volume and shape

• Tightly packed; Particles vibrate around fixed axes

• Its molecules have fixed positions because there is not enough thermal energy to overcome the IMF interaction between the particles

Liquid

• Definite volume no definite shape

• Relatively dense or slightly loose

• Partially overcomes IMF but their particles are still in close contact

• Free to move over each other yet still attracted to each other

Gas

• Neither definite volume or shape

• Extremely far apart

• Completely overcomes IMF so its particles move in random motion with little to no interaction with each other

• Highly compressible

“crystal”

Constituent particles arranged in a regular, three-dimensional array

“Amorphous” (without form)

Some solids cannot organize their particles in such regular crystals

Mercury

• An anomaly, it is the only metal we know that is liquid at room temperature.

• (has a 357c boiling point)

Change from Liquid to Gas 

significantly increases the volume of a substance, by a factor of 1000 or more.

Plasma

• Also a state of matter yet rarely happens naturally on earth

Pure Substance

A form of matter with a constant composition and constant properties throughout the sample.

• Has a fixed chemical composition and distinct properties

• Is the same everywhere

• Can only be separated through chemical methods and rarely physical

Element

Fundamental substances that cannot be separated into simpler substances by chemical methods (ex. Aluminum)

Compound

• A substance composed of 2 or more elements in fixed proportions

• Can be separated into simpler substances only by chemical methods.

• A molecule made of atoms from different elements.

• (ex. Water, Sodium Chloride, Carbon Dioxide)

Mixture

• Matter consisting of two or more pure substances that retain their individual identities and could be separated by physical methods

Homogeneous (solution)

• Mixture that has a uniform composition and properties throughout

• Is composed of a single phase

• (ex. Coffee, Wine, Air, Saltwater)

Heterogeneous

• A mixture that is not uniform in composition and properties throughout

• Is composed of two or more phases

• (ex. Vegetable soup)

Phase

• Is any part of a sample that has a uniform composition and properties.

More than one phase

Does not mix into a uniform composition. (ex: oil and water)