Chemistry: Matter and Energy Vocabulary

Chemical Change

A reaction in which the composition of a substance is changed

Chemical Property

Describes the way a substance will react or not react in a given situation

Chromotography

Separation of liquids based on polarity

Compound

a pure substance composed of two or more elements that are chemically combined in definite proportion

Diatomic

A molecule with two identical elements

What are the diatomic elements?

• Hydrogen (H₂)

• Nitrogen (N₂)

• Fluorine (F₂)

• Oxygen (O₂)

• Iodine (I₂)

• Chlorine (Cl₂)

• Bromine (Br₂)

Distillation

Separating two liquids based on their boiling point

Element

A substance that cannot be broken down by chemical means, found on the periodic table

Endothermic

Reaction that absorbs heat; heat enters the reaction

Evaporation

Separation of a dissolved solid from a liquid by heating and evaporating the liquid (often water)

Exothermic

Reaction that releases heat; heat exits the reaction

Filtration

Separation of a liquid and a solid based on particle size

Gas

phase of matter without definite shape or volume

Heterogeneous

a mixture in which the particles are not uniformly mixed, has layers

Homogeneous

a mixture in which particles are uniformly mixed, looks the same throughout

Liquid

phase of matter that has no definite shape, but has definite volume

Matter

anything with mass and volume

Mixture

substance physically combined in variable proportion

Particle Diagram

drawing of atoms and or molecules frozen in time as a solid, liquid, or gas and as an element, compound, or mixture

Physical Change

a change that doesn’t alter the chemical properties of a substance

Physical Property

a trait that describes the way something looks, feels, or smells or how much of a substance there is

Precipitate

the insoluble product of a reaction between two aqueous solutions

Solid

phase of matter with definite shape and volume