Question

Write a balanced chemical equation for the standard formation reaction of gaseous formaldehyde CH2O

Answer 1

From the combustion of octane, the formaldehyde will be formed as this equation:

C8H18 +  O2 → CH2O + H2O   this is the original equation but it is not a balanced equation, so let's start to balance it: 

the equation to be balanced so the number of atoms on the right side of the equation sholud be equal with the number of atoms on the lef side.

-we have 8 C atoms on left side and 1 atom on the right side so we will try putting 8 CH2O on the right side instead of CH2O

C8H18 + O2 → 8 CH2O + H2O 

we have 2 O atoms on the left side and  9 atoms on the right side so we will try first to put 9 O2 instead of O2 on the left side and put 2H2O on the right side and put  16 CH2O instead of 8 CH2O to make the atoms of O are equal on both sides = 18 atoms

C8H18 + 9 O2 →  16 CH2O + 2H2O 

put now we have 8 atom C on the left side and 16 atom on the right side so, we will put 2 C8H18 instead of C8H18 now we get this equation:

2C8H18 + 9O2 →16 CH2O + 2H2O

-now we have 36 of H atoms on both sides.

- and 16 of C atoms on both sides.

- and 18 of O atoms on both sides.

now all the number of atoms of O & C & H are equal on both sides

∴ 2C8H18 + 9O2 → 16 CH2O + 2 H2O 

is the final balanced equation for the formation of formaldehayde