State Information in Reaction Equations

State and Solution Information:

Information about the states of matter for the reactants and products may be included in a reaction equation. If so, the abbreviation for the state is written in parenthesis following the chemical formula.

States of Matter Abbreviations
State or Solution Information	Abbreviation
Solid	(s)
Liquid	(l)
Gas	(g)
Aqueous solution	(aq)
Precipitate (insoluble solid formed when two solutions are combined)	(ppt)

A reaction equation that shows the state information looks like this:

HCl_(g) + NH_3(g) à NH₄Cl_(s)

An older style of chemical reaction equation shorthand uses an upward pointing arrow to indicate a gas; a downward pointing arrow indicates a precipitate. In both cases, these symbols were almost exclusively used for products of aqueous reactions (ones in which water is the solvent).

Zn_(s) + H₂SO_4(aq) à ZnSO_4(aq) + H₂á

Miscellaneous Symbols

A small triangle written below the reaction arrow indicates that the reaction requires heat to proceed. Organic reactions (those involving the chemistry of carbon compounds) frequently have specific information about the temperature, solvent, and catalysts written above and below the reaction arrow. For complicated, multi-step reactions, this information is numbered to make a kind of recipe for the reaction sequence.

This site was last updated 09/13/06