compound,_3 atoms of carbon& 8 atoms of hydrogen & reaction W/oxygen molecules.?

Question

The two end products of this equation are carbon ddioxide (co2) and water. What element should you look at first in balancing this equation? I do not understand how to balance the ive tried and im lost.Is it hydrogen, carbon, or dioxide.

Answer 1

C3H8 + O2>>CO2 +H2O
C3H8 + 6H2O >>3CO2 +20H+ +20 e-
( 4e- + 4H+ + O2 >> 2H2O) 5
20e- + 20 H+ + 5O2 >> 10H2O
It is a redox equation that is possible balance by use of half-reaction always suggested
The steps to follow are these
1 separate the oxiding and the reducing agent
2 count up the number of oxigen atoms and add H2O to the side deficient in oxigen
3 count up the number of H and add H+ to the side deficient in H
4 count up the net charge and add e- to the side deficient in negative charge
5 to get a balanced reaction mulptiply each half-reaction so that when the 2 half-reaction are added up the electrons can be cancelled out
6 add up the half-reactions and cancel any duplication of species on the left and right side

In this way you will never go wrong

Answer 2

You are looking at a combustion reaction.

A C3H8 + B O2 --> C CO2 + D H2O

First balance the carbons. Assume A = 1 for starters. Therefore C must be 3.

Now balance the hydrogen A * 8 = D * 2 so D = 4.

Now see if the O's balance. C * 2 + D * 1 = 10, so B must be 5.

This works so you don't have to change A.