CHE-101 Chapter 1 Lecture Notes - Matter, Properties, and Changes

Vocabulary flashcards covering core foundational topics from CHE-101 Chapter 1 lecture notes, including states of matter, pure substances, compounds, mixtures, properties, and physical vs. chemical changes.

Chemistry

The branch of science focused on measuring and analyzing matter, how matter changes, and the energy associated with those changes.

Matter

Anything that has mass and takes up space.

Atom

The smallest building block of matter.

Molecule

A structure formed by $2$ or more atoms bonded together.

Gas

A state of matter with no fixed shape and no fixed volume that conforms to and completely fills its container, with atoms or molecules that are far apart and disorganized.

Liquid

A state of matter with no fixed shape but a fixed volume that conforms to its container without completely filling it, with atoms or molecules that are close together and somewhat disorganized.

Solid

A state of matter with a fixed shape and a fixed volume that does not conform to or fill its container, with atoms or molecules that are closely packed and rigidly organized.

Pure Substance

Matter that has distinct properties and a fixed composition that does not vary from sample to sample.

Element

A pure substance that cannot decompose into anything smaller, represented on the Periodic Table by $1$ or $2$ letters ($118$ known elements, $90$ of which are natural).

Atomic Element

An element made up of individual, separate types of single atoms, such as gold or solid copper.

Molecular Element

An element that exists in nature as molecules composed of similar atoms bonded together.

Diatomic Molecules

Molecules consisting of $2$ of the same atom attached together, comprising the $7$ elemental diatomics: $H_2$, $N_2$, $O_2$, $F_2$, $Cl_2$, $Br_2$, and $I_2$.

Compound

A pure substance made of molecules containing $2$ or more different elements connected or bonded in a fixed ratio, which can be decomposed into its respective elements.

Mixture

A non-pure combination of $2$ or more substances where each substance retains its original properties and the composition varies from sample to sample.

Homogeneous Mixture (Solution)

A mixture with uniform appearance and composition throughout, such as air or sugar water.

Heterogeneous Mixture

A mixture that does not have a uniform composition and appearance throughout, such as rocks or sand.

Physical Property

A characteristic of a substance describing its appearance that can be observed without changing its identity or chemical composition.

Intensive Property

A physical property that does not depend on how much of the sample is present, such as color, luster, hardness, melting point, density, phase, or conductivity.

Extensive Property

A physical property that depends on the quantity of sample present, such as mass, volume, length, or thickness.

Chemical Property

A characteristic describing how a substance reacts or interacts with other substances to form a new substance, such as corrosiveness, flammability, and reactivity towards acids or bases.

Physical Change

A change that alters the form or state of matter without altering its chemical identity, such as a reversible state change from $H_2O_{(l)}$ to gas upon heating.

Chemical Change (Chemical Reaction)

A transformation where starting substances turn into new, different substances, usually accompanied by indicators like color changes or bubble formation.