Ultimate Guide: IB Chemistry (HL)

Atom

The smallest part of an element.

Compound

A substance made up of two or more elements chemically bonded in a fixed ratio.

Mixture

A physical combination of two or more substances that retain their individual properties.

Homogeneous Mixture

A mixture that has a uniform composition throughout, like air.

Solid

A state of matter with a fixed shape and volume, where particles are closely packed.

Liquid

A state of matter with a fixed volume and no fixed shape, taking the shape of its container.

Gas

A state of matter that fills its container, with widely spaced particles.

Sublimation

The transition of a substance from solid to gas without passing through the liquid state.

Mole

A unit of measurement in chemistry that represents 6.02 x 10^23 particles of a substance.

Empirical Formula

A formula that shows the simplest whole-number ratio of atoms in a compound.

Molecular Formula

A formula that indicates the actual number of atoms in a molecule.

Ionic Compound

A compound formed by the electrostatic attraction between oppositely charged ions.

Chemical Reaction

A process that leads to the transformation of one set of chemical substances to another.

Balanced Equation

An equation in which the number of each type of atom is equal on both sides of the equation.

Gas Laws

Laws that describe the behavior of gases under varying conditions of temperature and pressure.

Avogadro's Constant

The number of particles in one mole of a substance, approximately 6.022 x 10^23.

Enthalpy (ΔH)

The heat content of a system at constant pressure.

Exothermic Reaction

A chemical reaction that releases heat to its surroundings.

Endothermic Reaction

A chemical reaction that absorbs heat from its surroundings.

Catalyst

A substance that increases the rate of a chemical reaction without being consumed.

Dynamic Equilibrium

A state in which the rates of the forward and reverse reactions are equal.

Ionization Energy

The energy required to remove an electron from an isolated atom.

Electronegativity

The ability of an atom to attract electrons in a chemical bond.

Oxidation

The loss of electrons during a chemical reaction.

Reduction

The gain of electrons during a chemical reaction.

Spectroscopy

A technique used to identify substances based on their interaction with electromagnetic radiation.

Isotope

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