Matter Unit 3 - Lecture Flashcards

Vocabulary flashcards based on the 'Matter Unit 3' lecture notes.

Matter

Anything that has mass and occupies space. It cannot be created or destroyed; it can only change forms.

Pure Substance

Matter with a fixed composition (elements, compounds).

Mixture

Matter with a variable composition.

Atom

The fundamental unit of matter, composed of protons, neutrons, and electrons. It is defined by the number of protons in the nucleus.

Element

A pure substance that cannot be chemically broken down, consisting of only a single type of atom, defined by the number of protons.

Diatomic Element

An element that exists naturally with two atoms in its elemental formula (e.g., hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine).

Compound

Consists of two or more different atoms bound together.

Homogeneous Mixture

A mixture that is uniform throughout (e.g., air, saltwater).

Heterogeneous Mixture

A mixture that is not uniform (e.g., salad, sand + water).

Physical Properties

Characteristics of matter that can be changed without changing its composition and are directly observable (e.g., odor, color, volume, state, density, melting point, boiling point).

Chemical Properties

A substance's ability to form new substances; characteristics that describe how the composition of matter changes as a result of contact with other matter or the influence of energy (e.g., flammability, rusting of steel, digestion of food).

Physical Change

A change in a physical property that retains the identity of the substance (e.g., a change of state, size, or shape).

Chemical Change

A change in which the original substance is converted to one or more new substances (e.g., paper burns, iron rusts, silver tarnishes).