Read the given passage and answer any four questions.
The symbols for solids, (s) for liquids, (g) for gases, and (aq) for an aqueous solution together with their associated equations can be used to denote the physical states of the reactants and products. If the reactant or product is present as a solution in water, the word aqueous is used. Instead of the symbol(s), an arrow pointing downward  $( \downarrow )$ might be used to denote the residue.
Similarly, the symbol(g) for the gaseous state of an evolved gas might be replaced with an arrow going upward $(\uparrow )$. In the chemical equation, the specific conditions of the reaction, such as temperature, pressure, catalyst, etc., are indicated above or below the arrow.