General Chemistry Lecture: Introduction and Matter Classification

A set of vocabulary flashcards covering the fundamental definitions, classifications of matter, atomic features, states of matter, and physical laws discussed in the lecture.

Chemistry

The study of substances, their composition and structure, and the changes they undergo.

Atom

The building block of ordinary matter and the smallest unit of an element, composed of protons, neutrons, and electrons.

Proton

The subatomic particle located in the nucleus that identifies what element an atom is and does not change during a chemical reaction.

Atomic Number

The whole number on the periodic table that identifies an element by the number of protons inside its nucleus, such as $6$ for carbon.

Mass Number

The number on the periodic table that represents the average masses of an element's atoms.

Molecule

Two or more atoms bonded together, which can be the same or different, specifically describing nonmetal and nonmetal combinations such as $O_2$.

Compound

A substance made of two or more different elements combined in a specific ratio, such as water ($H_2O$).

Molecular Compound

A compound made entirely of nonmetals.

Ionic Compound

A compound that contains metal elements.

Law of Conservation of Mass

A law stating that in a chemical reaction, matter is neither created nor destroyed.

Law of Conservation of Energy

A law stating that energy cannot be created or destroyed, but can be transformed or transferred from one form to another.

Solid

A state of matter that has a definite shape and volume, whose constituent atoms move via vibration.

Liquid

A state of matter that has a definite volume but no definite shape, and is slightly compressible.

Gas

A state of matter that has no definite volume or shape and is highly compressible due to its atoms being far apart.

Compressibility

The measure of how much a substance can be squeezed down, which is highest in gases.

Crystalline Solid

A solid whose atoms and molecules have a very ordered, long-range pattern, such as diamonds or table salt.

Amorphous Solid

A solid that lacks a long-range pattern in its atomic arrangement, such as glass or plastic.

Mohs Scale

A scale used in geology to determine the hardness of minerals, on which diamond is ranked as number $10$.

Plasma

A state of matter demonstrated when microwave radiation interacts with a green grape to produce a bright light and localized gas.

Aqueous Solution

A solution formed with water, such as an acid solution or a saltwater solution.

Pure Substance

A classification of matter made up of only one component, divided into elements and compounds.

Element

A pure substance that cannot be broken down into simpler substances.

Mixture

A classification of matter consisting of two or more components in varying proportions.

Heterogeneous Mixture

A mixture that has non-uniform properties or different components throughout, such as a salad or wet sand.

Homogeneous Mixture

A mixture that has uniform components and properties throughout, such as Kool-Aid, coffee, tea, sodas, or beer.