Question

question 19 (5 points)
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which of the following is the balanced chemical equation for the combustion of methane, ch4?
a) 2ch4 (g) + o2 (g) → 2co2 (g) + h2o (g)
b) ch4 (g) + 2o2 (g) → co2 (g) + 2h2o (g)
c) ch4 (g) + 2o2 (g) → co2 (g) + h2o (g)
d) ch4 (g) + 2o2 (g) → 2co2 (g) + 2h2o (g)

Explanation:

To balance the combustion of methane ($\ce{CH4}$), we check the number of each atom on both sides. For option B: On the left, $\ce{C}$: 1 (from $\ce{CH4}$), $\ce{H}$: 4 (from $\ce{CH4}$), $\ce{O}$: 4 (from $2\ce{O2}$). On the right, $\ce{C}$: 1 (from $\ce{CO2}$), $\ce{H}$: 4 (from $2\ce{H2O}$), $\ce{O}$: 4 (2 from $\ce{CO2}$ + 2 from $2\ce{H2O}$). All atoms are balanced. Other options have unbalanced atoms (e.g., A has unbalanced $\ce{H}$ and $\ce{O}$, C has unbalanced $\ce{H}$, D has unbalanced $\ce{C}$).

Answer:

B) $\ce{CH4 (g) + 2O2 (g) -> CO2 (g) + 2H2O (g)}$