Matter and Measurement - Key Concepts Flashcards

A set of vocabulary-style flashcards covering key terms from the lecture notes on matter, measurement, atomic structure, ionic/m molecular compounds, and related concepts.

Matter

Anything that has mass and occupies space.

Atom

The fundamental building block of elements; the basic unit of matter that cannot be created or destroyed in chemical processes.

Molecule

Two or more atoms bound together in a specific arrangement; can involve different elements or the same element.

Element

A substance that contains only one type of atom.

Compound

A substance containing more than one type of element chemically combined in fixed proportions.

Pure substance

A substance with a distinct set of properties and a constant composition.

Mixture

A blend of two or more substances with variable composition.

Heterogeneous

Mixtures that are not uniform in composition; parts can often be seen.

Homogeneous

Mixtures or substances that are uniform throughout; pure substances are homogeneous.

Solid

State of matter with a definite shape and volume; particles are close together and not easily compressible.

Liquid

State of matter with definite volume but no fixed shape; takes the shape of its container.

Gas

State of matter with no definite shape or volume; highly compressible and fills space available.

Intensive property

A property that does not depend on the amount of substance present.

Extensive property

A property that depends on the amount of substance present.

Physical change

A change that does not alter the chemical identity of a substance (e.g., boiling water).

Chemical change

A change that alters the substance's composition and identity (e.g., burning octane).

Physical property

A property observable without changing the composition (e.g., color, melting point, density).

Chemical property

A property related to how a substance undergoes chemical change (e.g., flammability, acidity).

Density

Mass per unit volume; an intensive property used to identify substances.

Mass

The amount of matter in a sample; an extensive property.

Volume

The amount of space a substance occupies; an extensive property.

SI base units

Base units: kilogram (mass), meter (length), second (time), Kelvin (temperature), mole (amount of substance).

Prefixes (metric)

Metric prefixes used with base units (tera-, giga-, mega-, kilo-, deci-, centi-, milli-, micro-, nano-, pico-). Abbreviations: T, G, M, k, d, c, m, μ, n, p.

Scientific notation

Expressing numbers as a × 10^n with a between 1 and 10 to handle very large or small values.

Uncertainty in measurement

Measured numbers can be exact or inexact; inexact numbers have some uncertainty.

Significant figures

Digits that carry meaningful information about precision in a measured or calculated value.

Exact numbers

Numbers with no uncertainty defined by definition (e.g., 12 items in a dozen; 1000 g in 1 kg).

Atomic number

The number of protons in the nucleus; defines the identity of an element.

Mass number

Total number of protons and neutrons in the nucleus.

Isotopes

Atoms of the same element with the same number of protons but different numbers of neutrons.

Atomic weight

Average atomic mass of an element, weighted by isotopic abundances.

Ions

Atoms that have gained or lost electrons, giving a net electrical charge.

Cation

A positively charged ion (fewer electrons than protons).

Anion

A negatively charged ion (more electrons than protons).

Ionic compound

A compound formed from ions with a crystal lattice structure and fixed ratios (not discrete molecules).

Empirical formula

The simplest whole-number ratio of ions in an ionic compound.

Polyatomic ion

A charged entity composed of more than one atom acting as a unit (e.g., NH4+, SO4^2-).

Binary ionic compound naming

Name the cation first, then the anion; use Roman numerals for transition metals to indicate charge; polyatomic ions are named as such.

Molecular compounds

Compounds composed of nonmetals that form molecules via covalent bonds.

Diatomic molecules

Molecules consisting of two atoms: H2, N2, O2, F2, Cl2, Br2, I2.

Prefix naming for binary molecular compounds

Use Greek prefixes to denote subscripts (mono-, di-, tri-, etc.); second element ends with -ide; omit 'mono' for the first element.

Common diatomic molecules (examples)

H2, N2, O2, F2, Cl2, Br2, I2.

Empirical vs. molecular formula

Empirical formula shows the simplest whole-number ratio; molecular formula shows the actual number of atoms in a molecule.