Consider the oxidation of sodium metal to sodium oxide described by the balanced equation: 4 Na (s) + O2 (g) → 2 Na2O (s) As you can see there are letters in parentheses after each substance. Show you know the meaning of these letters by filling in what they stand for:

s stands for solid

g stands for gas

Explanation:

Na_{ (s) } + O_{2 (g) } → 2Na_{2}O_{s}

The lettered subscript describes the state of the matter of the reacting atoms, compounds and molecules. It also shows the state of matter of the products formed.

s stands for solid

g stands for gas

Some other reactions have l which is liquid and aq which is aqeous.