Here's what that implies:
* State: The substance is not in its solid, liquid, or gaseous form, but rather dissolved in water.
* Polarity: Water is a polar solvent, so substances labeled "aq" are likely to be polar or ionic compounds.
* Solubility: The substance has a high affinity for water and dissolves readily in it.
Example: NaCl (aq) indicates that sodium chloride (table salt) is dissolved in water.
