Balance this equation. If a coefficient of "1" is required, choose

CH4 + 2O2 -> CO2 + 2H2O

Blank box Ch4+2O2

Box CH 4 + boxed 2 o 2

To balance the equation CH4 + O2 → CO2 + H2O, we need to make sure that there is an equal number of atoms on both sides of the equation.

Let's start by counting the number of atoms for each element on both sides of the equation:

CH4: 1 carbon (C) and 4 hydrogen (H)
O2: 2 oxygen (O)
CO2: 1 carbon (C) and 2 oxygen (O)
H2O: 2 hydrogen (H) and 1 oxygen (O)

Currently, the equation has an imbalance in the number of hydrogen and oxygen atoms. To balance the hydrogen atoms, we can place a coefficient of 2 in front of H2O:

CH4 + O2 → CO2 + 2H2O

Now, let's recount the number of atoms on each side of the equation:

CH4: 1 carbon (C) and 4 hydrogen (H)
O2: 2 oxygen (O)
CO2: 1 carbon (C) and 2 oxygen (O)
2H2O: 4 hydrogen (H) and 2 oxygen (O)

The hydrogen atoms are now balanced, but the oxygen atoms are still imbalanced. On the left side, we have 2 oxygen atoms, while on the right side, we have 4 oxygen atoms. To balance the oxygen atoms, we can place a coefficient of 2 in front of O2:

CH4 + 2O2 → CO2 + 2H2O

Now, let's count the number of atoms again:

CH4: 1 carbon (C) and 4 hydrogen (H)
2O2: 4 oxygen (O)
CO2: 1 carbon (C) and 2 oxygen (O)
2H2O: 4 hydrogen (H) and 2 oxygen (O)

Both hydrogen and oxygen atoms are now balanced on both sides of the equation. The balanced equation is:

CH4 + 2O2 → CO2 + 2H2O