Question

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest, whole-number coefficients? ________ C2H6O (l) + ________ O2(g) → ________ CO2(g) + ________ H2O(l)

Answer 1

The answers are:  1 (so leave blank);  3 ; 2 ; 3 .
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                C₂H₆O (l) + 3 O₂ (g) → 2 CO₂ (g) + 3 H₂O (l)
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Answer 2

Answer: The stoichiometric coefficient of $O_2$ is 3.

Explanation:

Every balanced chemical equation follows Law of conservation of mass.

This law states that mass can neither be created nor be destroyed, but it can only be transformed from one form to another form.

This also means that the total number of individual atoms on the reactant side must be equal to the total number of individual atoms on the product side.

For the balanced chemical equation:

$C_2H_6O(l)+3O_2(g)\rightarrow 2CO2(g)+3H_2O(l)$

On reactant side:

Number of Carbon atoms = 2

Number of Hydrogen atoms = 6

Number of Oxygen atoms = 7

On product side:

Number of Carbon atoms = 2

Number of Hydrogen atoms = 6

Number of Oxygen atoms = 7

Hence, the coefficient of $O_2$ in the balanced chemical equation is 3.