Consider the following intermediate chemical equations.

CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (g)

2H2O (g) → 2H2O (1)

Which overall chemical equation is obtained by combining these intermediate equations?

CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (1)

CH4 (g) + 202 (g) → CO2 (g) + 2H2O (g)

CH4 (g) + 2O2 (g) → CO2 (g) + 4H2O (g) + 2H2O (1)

CH4 (g) + 2O2 (g) → CO2 (g) + 6H2O (g)

Answer: The reaction is Exothermic

CH4 (g) + 2O2 (g) > CO2 (g) + 2H2O (g) + energy

CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (l).

Explanation:

We have two equations:

CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (g)

2H₂O (g) → 2H₂O (l)

To add the two equations: we omit H₂O (g) that is formed by 2 moles in the product side of the first equation and consumed by 2 moles from the reactants side in the second equation

So, the overall chemical equation is obtained by combining these intermediate equations is:

CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (l).