Question

Given the incomplete equation representing a reaction: 2C6H14 + ______ O2 → 12CO2 + 14H2O What is the coefficient of O2 when the equation is completely balanced using the smallest whole-number coefficients?

Answer 1

The coefficient of O2 is 19 since their are 38 oxygen atoms on the product side and each O2 molecule has 2 atoms.  38/2=19

Answer 2

Answer : The coefficient of $O_2$ used is, 19

Explanation :

Law of conservation of matter : It states that the number of atoms of each element on reactant side should be equal to the product side in the chemical reaction.

In the unbalanced reaction, the number of atoms of hydrogen and carbon is balanced but the number of atoms of oxygen are not balanced. As, there are 2 number of atoms of oxygen on reactant side and there are 38 number of atoms of oxygen on product side. So, for the balanced oxygen we multiply the reactant oxygen by the whole number 19.

The given balanced reaction will be,

$2C_6H_{14}+19O_2\rightarrow 12CO_2+14H_2O$

Hence, the smallest whole-number coefficient of  used for balanced chemical reaction is, 19