Let's examine the chemical reaction given:
[tex]\[ CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O \][/tex]
To determine which compound is a product from the reaction, we need to identify the substances on both sides of the reaction equation:
- Reactants (substances you start with) are on the left side of the arrow:
- [tex]\( CH_4 \)[/tex] (methane)
- [tex]\( 2O_2 \)[/tex] (oxygen)
- Products (substances you end up with) are on the right side of the arrow:
- [tex]\( CO_2 \)[/tex] (carbon dioxide)
- [tex]\( 2H_2O \)[/tex] (water)
Now, let's match these products with the options given in the question to see which one is listed as a product:
1. [tex]\( O_2 \)[/tex] - This is a reactant, not a product.
2. [tex]\( H_4 \)[/tex] - This does not appear in the reaction at all.
3. [tex]\( H_2O \)[/tex] - This is a product of the reaction.
4. [tex]\( CH_4 \)[/tex] - This is a reactant, not a product.
From these choices, [tex]\( H_2O \)[/tex] (water) is the correct answer because it is one of the products of the reaction.
Therefore, the correct answer is:
[tex]\[
\boxed{3}
\][/tex]
