Chemical Equations

Vocabulary terms and historical facts regarding the structure, components, and symbols used in chemical equations.

Chemical Equation

A symbolic representation of a chemical reaction that occurred.

Jean Beguin

The French chemist credited with the first usage of a chemical equation in 1615.

Reactants

Substances going through a chemical reaction, typically located on the left side of the arrow.

Products

Substances generated by the chemical reaction, typically located on the right side of the arrow.

Plus Sign ($+$)

A symbol used to separate multiple reactants or multiple products in a chemical equation.

Reaction Arrow

A symbol that indicates the direction of the reaction.

Forward Arrow ($\rightarrow$)

A symbol used for irreversible reactions that go to completion.

Equilibrium Arrow ($\rightleftharpoons$)

Indicates simultaneous reactions occurring in both directions until reactants and products remain at equilibrium.

Reversible Arrow ($\rightleftarrows$)

Indicates a reaction that may happen in the direction towards the left or right but does not happen at the same time.

Coefficient

A number indicating stoichiometry or how many of a substance is present; if the value is 1, it is omitted.

Subscript

A number indicating how many atoms of an element are present in a particular molecule.

State of Matter ($s$)

Notation indicating a substance is in solid form.

State of Matter ($l$)

Notation indicating a substance is in liquid form.

State of Matter ($g$)

Notation indicating a substance is in gas form.

State of Matter ($aq$)

Notation indicating substances dissolved in an aqueous solution.

Delta ($\Delta$)

The Greek letter used to indicate that heat is being used in a reaction.