CramX Logo

Q
QuestionChemistry

Explain why oxygen gas must be written as O^2 in a chemical equation.
12 months agoReport content

Answer

Full Solution Locked

Sign in to view the complete step-by-step solution and unlock all study resources.

Step 1:
:

To understand why oxygen gas is written as O^2 in a chemical equation, it is essential to know that oxygen is a diatomic molecule. This means that one molecule of oxygen consists of two oxygen atoms chemically bonded together.

Step 2:
:

In a chemical equation, we represent the actual number of atoms of each element involved in a reaction. Therefore, when writing an equation for a reaction involving oxygen, we need to account for the fact that each oxygen atom exists as part of an O^2 molecule.

Step 3:
:

For example, consider the complete combustion of methane (CH4): CH^4 + 2O^2 → CO^2 + 2H^2O Here, the coefficient 2 in front of O^2 indicates that two molecules of oxygen gas (O2) are required for the complete combustion of one molecule of methane (CH4).

Step 4:
:

To further illustrate this concept, let's look at the number of oxygen atoms on both sides of the equation: CH^4 + 2O^2 → CO^2 + 2H^2O On the left side, there are 2 oxygen atoms from the O^2 molecules. On the right side, there are 2 oxygen atoms in CO^2 and 4 oxygen atoms in 2H^2O, making a total of 6 oxygen atoms. Since the number of oxygen atoms is equal on both sides, the equation is balanced, and the role of the diatomic O^2 molecule is clear.

Final Answer

Oxygen gas is written as O^2 in a chemical equation because oxygen exists as a diatomic molecule, with two oxygen atoms chemically bonded together. This notation ensures that chemical equations accurately represent the actual number of atoms of each element involved in a reaction.