Symbols are written in parentheses to the right of the reactants and products in a chemical equation to indicate whether they are solids, liquids, gases, aqueous, or a precipitate. The symbols are as follows:
(s) means solid (also frequently used for precipitates)
(l) means liquid
(g) means gas
(aq) means aqueous (meaning dissolved in water)
1) Aqueous silver nitrate plus aqueous sodium chloride react to produce aqueous sodium nitrate and solid silver chloride (silver chloride as a precipitate).
Since the product
2) Methane gas plus oxygen gas react to produce carbon dioxide gas and liquid water.
3) Solid copper metal plus aqueous silver nitrate react to produce solid silver metal plus aqueous copper(II) nitrate.