Key Vocabulary: Matter and Chemical Reactions

Flashcards covering key vocabulary from lecture notes on matter, atoms, elements, compounds, mixtures, states of matter, and chemical reactions.

Atom

The smallest particle that builds elements, derived from the Greek word 'atomos' meaning indivisible.

Element

A substance made up of atoms of the same kind.

Pure Substance

A substance made of only one type of atoms or molecules with the same chemical composition.

Element (Pure Substance)

A pure substance made of only one type of atom.

Compound (Pure Substance)

A pure substance with a uniform chemical composition where each molecule contains the same types and numbers of atoms in the same proportions.

Protons

Positively charged particles found in the nucleus of an atom.

Neutrons

Neutral particles (no charge) found in the nucleus of an atom.

Electrons

Particles found around the central part (nucleus) of the atom.

Nucleus

The central part of the atom containing protons and neutrons.

Element

A substance made of atoms of only one kind, examples include hydrogen, oxygen and carbon.

Diatomic Molecules

Elements that form molecules consisting of two atoms, such as hydrogen (H2), nitrogen (N2), and oxygen (O2)

Compound

A pure substance made of atoms of two or more different elements chemically bonded in fixed ratios.

Molecule

Two or more atoms of the same or different elements that are chemically bonded; the smallest unit in a compound.

Chemical Bond

The force that holds atoms together in a chemical reaction.

Mixture

A substance made of substances that can be physically separated.

Homogenous Mixture

A mixture that is uniform in composition throughout, where substances cannot be distinguished from each other.

Matter

Anything that has mass and can occupy space.

Particle Model of Matter

A theory used to explain the changes of state in matter, stating that all matter is made of very small particles that are always in motion.

Volume

The amount of space that matter takes up.

Mass

The amount of matter an object has.

Evaporation

Change of a substance from liquid to gas.

Freezing

Substance changing from liquid to solid.

Melting

When a substance changes from solid to liquid.

Sublimation

Change of matter from solid to gas.

Deposition

The change of gas to solid.

Expansion

When particles in a material gain energy and move further apart, causing the material to increase in size.

Contraction

When a material shrinks (gets smaller) when cooled down due to a loss in energy that makes the particles move closer.

Pressure

The amount of force applied over a given area.

Reactants

The substances reacting with each other to form new substances in a chemical reaction.

Products

The new substances formed as a result of a chemical reaction.

Chemical Equation

A symbolic representation of a chemical reaction.

Density

Mass per unit volume.