Elements, Molecules, Compounds, and Phase Changes: Key Terms and Definitions

absolute zero

The temperature at which all atoms and molecules stop vibrating. O Kelvin or -273.15 °C

atom

The smallest particle of an element

BEC - Bose-Einstein Condensate

State of matter that has the least amount of energy.

Atoms and molecules stop vibrating independently and move together like one giant atom.

Boiling

vaporization of a liquid

Compound

A substance that contains two or more different kinds of atoms chemically bonded together.

Condensation

Phase change from a gas to a liquid.

Deposition

Phase change from a gas to a solid. (skip liquid)

Element

A substance that can not be broken down into simpler substances. You can find it on the periodic table

Endothermic (adding heat)

When thermal energy (heat) is being added /

Think endo=INTO

solid to liquid (melting)

liquid to gas (vaporization)

Solid to gas (Sublimation)

Evaporation

The gradual vaporization of a liquid on the surface.

Exothermic (giving off heat)

When a substance is losing thermal energy (heat)

gas to liquid (condensation)

liquid to solid (freezing)

gas to liquid (deposition)

Freezing

Phase change from a liquid to a solid.

Gas

State of matter where all the atoms and molecules are independant of each other and move around randomly

Heterogeneous

When a substance looks like it is made of 2 or more things.

Chunk Salsa

Chocolate chip cookie

Homogeneous

When a substance looks like it is all the same throughout.

vanilla milkshake

peanut butter cookie

Liquid

State of matter where all the atoms and molecules are able to move around but they all stay grouped together.

Matter

Anything that has both volume (takes up space) and mass

Melting

Phase change from a solid to a liquid.

Mixture

Two or more substances combined that

CAN be separated

Molecule

Two or more atoms together.

Phase Change

Changing state of matter.

Plasma

State of matter that is higher energy than a gas.

Pure Substance

A substance that is made of only one type of atom (O or O₂) or one type of compound (CO₂).

Solid

State of matter where all the atoms and molecules are arranged in a neatly ordered pattern.

Sublimation

Phase change from solid to a gas (skip liquid)

Vaporization

Phase change from liquid to gas which includes...

...boiling

...evaporation

Examples of Solutions

salt water, coffee (no creamer), sugar water, Kool-aid, Coke, vinegar

Examples of Elements

carbon (C), oxygen (O),

nitrogen (N), chlorine (Cl)

Examples of Compounds

Water (H₂O), Sugar, Salt, Baking Soda, Baking Powder

Examples of Mixtures

soapy water, shells in sand, dirty water

Examples of Homogeneous things

tomato soup, salt water, legs of your desk, post-it note, plain hummus

Examples of Heterogenous things

vegetable soup, mixed jar of candy, junk drawer, cookie dough ice cream, Snickers bar

Exothermic (giving away heat) ←

Going from Liquid to solid, gas to liquid or gas to solid causes the atoms to move less. The material LOSES energy.