Chemistry Glossary

A substance that donates protons ($\text{H}^+$ ions) to another substance or accepts an electron pair in a chemical reaction.

The minimum energy required by reactant molecules to initiate a chemical reaction.

A negatively charged ion formed when an atom gains one or more electrons.

The electrode at which oxidation (loss of electrons) occurs in an electrochemical cell.

The constant $6.022 \times 10^{23}$, representing the number of particles in one mole of any substance.

A substance that accepts protons ($\text{H}^+$ ions) or donates an electron pair in a chemical reaction.

A substance that increases the rate of a chemical reaction by lowering the activation energy without being permanently consumed.

The electrode at which reduction (gain of electrons) occurs in an electrochemical cell.

A positively charged ion formed when an atom loses one or more electrons.

A pure substance composed of two or more different elements chemically bonded in a fixed ratio.

A chemical bond formed by the sharing of one or more pairs of electrons between two atoms.

A measure of the tendency of an atom to attract a bonding pair of electrons toward itself.

A thermodynamic property representing the total heat content of a system at constant pressure.

A measure of the disorder or randomness of a system, tending to increase in spontaneous processes.

The state in a reversible reaction where the rates of the forward and reverse reactions are equal and concentrations remain constant.

Describes a process or reaction that releases heat energy to the surroundings.

A chemical bond formed by the electrostatic attraction between oppositely charged ions resulting from electron transfer.

One of two or more compounds that have the same molecular formula but differ in structural arrangement or spatial orientation.

The mass of one mole of a substance, expressed in grams per mole (g/mol).

The SI unit for amount of substance, equal to $6.022 \times 10^{23}$ particles of that substance.

A chemical process in which an atom, ion, or molecule loses one or more electrons, increasing its oxidation state.

A logarithmic scale that measures the hydrogen ion concentration of a solution, indicating its acidity or basicity.

A chemical process in which an atom, ion, or molecule gains one or more electrons, decreasing its oxidation state.

The calculation of relative quantities of reactants and products in chemical reactions based on balanced equations.

An electron in the outermost energy level of an atom that participates in chemical bonding.