Chemistry 101 Foundations: Matter, States, and Measurement

Vocabulary flashcards covering core concepts from the lecture notes.

Matter

Anything that has mass and takes up space.

Mass

A measure of how much matter an object contains; usually measured in grams or kilograms.

Volume

The amount of space that a substance or object occupies.

Gas

A state of matter with no definite volume or shape; fills its container and is highly compressible.

Liquid

A state of matter with a definite volume but no fixed shape; flows and can take the shape of its container; slightly compressible.

Solid

A state of matter with definite shape and volume; very little compressibility.

Plasma

The fourth state of matter—an ionized gas with free electrons and ions; extremely hot and luminous.

Compressibility

The ability of a substance to decrease in volume under pressure; gases are highly compressible, liquids less, solids very little.

Expansion

The increase in volume with temperature; gases expand much more than liquids or solids; expansion in solids and liquids is small.

Kinetic Molecular Theory

A model explaining the behavior of matter by particles in constant, random motion unless restrained; helps explain states and changes.

Qualitative Observation

An observation that describes properties or categories (color, state, texture) without numeric data.

Quantitative Observation

An observation that involves numeric measurements (mass, volume, temperature) with units.

Units

Standard quantities used to express measurements (grams, liters, seconds); essential for accurate calculations.

Law

A concise description that summarizes observed phenomena; explains what happens but not why.

Theory

An explanatory model that explains why phenomena occur; testable and refinable based on evidence.

Hypothesis

A tentative explanation or educated guess that can be tested by experiments and may become a theory.

Atomic Theory

The idea that matter is composed of atoms; atoms are rearranged, not created or destroyed, in ordinary chemical reactions.

Conservation of Matter

In chemical reactions, total mass remains constant because atoms are conserved and simply rearranged.

Stoichiometry

The calculation of reactant and product quantities in a chemical reaction using a balanced equation.

Chemical Equation

A symbolic representation of a chemical reaction showing reactants and products with their relative amounts; balanced to conserve atoms.

Combustion Reaction

A chemical reaction with oxygen that releases heat; hydrogen and oxygen form water, often producing substantial energy.

Energy–Mass Relation (E=mc^2)

The principle that energy and mass are interchangeable; with everyday chemical reactions the mass change is too small to observe.