Chemistry Unit 2: Matter, Its Properties, and Changes Test Review

Vocabulary flashcards covering core concepts from Chemistry Unit 2, including classifications of matter, properties, types of changes, and the organization of the periodic table.

Element

A pure substance that cannot be broken down into simpler substances by chemical means and is composed of only one kind of atom (e.g., nitrogen).

Compound

A pure substance formed when two or more different elements chemically combine in a fixed ratio, such as salt ($NaCl$) or dry ice ($CO_2$).

Pure Substance

Matter that has a constant composition and consistent properties throughout; classified as either an element or a compound.

Physical Property

A characteristic of a substance that can be observed or measured without altering the substance's chemical composition or identity.

Chemical Property

A characteristic that describes the ability of a substance to undergo changes that transform it into one or more new substances.

Extensive Property

A physical property that depends on the amount of matter present in a sample, such as mass or volume.

Intensive Property

A physical property that remains the same regardless of the amount of matter present, such as density, boiling point, or color.

Physical Change

A change affecting the form or state of a chemical substance without changing its chemical identity, such as ice melting, liquid evaporating, or gas pressure increasing.

Chemical Change

A process where chemical bonds are broken and formed to produce one or more new substances with different compositions, such as paper burning, metal rusting, or food digesting.

Homogeneous Mixture

A mixture with a uniform composition and particle distribution throughout, exhibiting only a single visible phase (e.g., rainwater).

Heterogeneous Mixture

A mixture with a non-uniform composition in which different components or phases remain distinct and unevenly distributed (e.g., granite, granola bar, oil-and-vinegar salad dressing).

Solid State (Particle Arrangement)

A state of matter characterized by particles that are closely packed together in fixed, orderly positions and vibrate in place.

Liquid State (Particle Arrangement)

A state of matter where particles are close together but can move and slide past one another, allowing the substance to flow and take the shape of its container.

Gas State (Particle Arrangement)

A state of matter in which particles are widely separated from each other and move rapidly and randomly in all directions.

Period

A horizontal row of elements in the periodic table.

Group

A vertical column of elements in the periodic table whose members typically share similar chemical properties.

Noble Gases

The elements located in Group 18 of the periodic table, known for being generally unreactive.

Metals (State at Room Temperature)

A group of elements that are predominantly solid at room temperature.

Boron ($B$)

The chemical element located in Period 2, Group 13 of the periodic table.

Catalyst

A substance that facilitates or speeds up a chemical change without being consumed or permanently altered in the reaction.