The following chemical equation shows the incomplete formula for burning methanol. The question mark represents the unknown number of oxygen (O2) molecules. How many molecules of O2 are needed to balance this chemical equation?

Question

*
1 point
Captionless Image
1
3
5
6

Answer 1

The balanced equation for burning methanol is:

CH3OH + ?O2 -> CO2 + H2O

To balance the equation, we need to determine the unknown number of O2 molecules.

Looking at the carbon (C) and hydrogen (H) atoms on both sides of the equation, we see that they are already balanced.

On the left side, we have 1 carbon (C) atom, while on the right side, we have 1 carbon (C) atom in CO2. This is balanced.

On the left side, we have 4 hydrogen (H) atoms, while on the right side, we have 2 hydrogen (H) atoms in H2O. This is also balanced.

Therefore, the only thing left to balance is the oxygen (O) atoms.

On the left side, we have 1 oxygen (O) atom in CH3OH, while on the right side, we have 2 oxygen (O) atoms in CO2 and 1 oxygen (O) atom in H2O. This gives a total of 3 oxygen (O) atoms on the right side.

Since we need an equal number of oxygen (O) atoms on both sides, we need ? = 3 O2 molecules.

Therefore, we need 3 molecules of O2 to balance this chemical equation. Answer: 3.