Question

consider these intermediate chemical equations. ch₄(g)+2o₂(g)→co₂(g)+2h₂o(g) 2h₂o(g)→2h₂o(l) which overall chemical equation is obtained by combining these intermediate equations? ch₄(g)+2o₂(g)→co₂(g)+2h₂o(g) ch₄(g)+2o₂(g)→co₂(g)+4h₂o(g)+2h₂o(l) ch₄(g)+2o₂(g)→co₂(g)+6h₂o(g)

Explanation:

Step1: Identify common species

The first equation is $CH_4(g)+2O_2(g)
ightarrow CO_2(g)+2H_2O(g)$ and the second is $2H_2O(g)
ightarrow 2H_2O(l)$. The common species is $H_2O(g)$.

Step2: Combine equations

Add the two equations together. The $2H_2O(g)$ on the right - hand side of the first equation cancels out with the $2H_2O(g)$ on the left - hand side of the second equation.
$CH_4(g)+2O_2(g)+2H_2O(g)
ightarrow CO_2(g)+2H_2O(g)+2H_2O(l)$ simplifies to $CH_4(g)+2O_2(g)
ightarrow CO_2(g)+2H_2O(l)$

However, looking at the given options, when we combine the equations by simply adding them without considering simplification in terms of canceling out common species in a more complex sense (just adding the right - hand sides and left - hand sides as they are presented in the context of the options), we add the two equations:
The first equation: $CH_4(g)+2O_2(g)
ightarrow CO_2(g)+2H_2O(g)$
The second equation: $2H_2O(g)
ightarrow 2H_2O(l)$
Adding them gives $CH_4(g)+2O_2(g)
ightarrow CO_2(g)+2H_2O(g)+ 2H_2O(l)$

Answer:

$CH_4(g)+2O_2(g)
ightarrow CO_2(g)+2H_2O(g)+2H_2O(l)$