Balancing equations C2H6 + O2 => 3H2O + 2CO2

Question

chemical balance this equation C2H6 + O2 => 3H2O + 2CO2

Answer 1

C₂H₆ + O₂ => 3H₂O + 2CO₂

Notice that there are the same number of carbons (C) on each side and there are the the same number of hydrogens (H) on each side so the issue is the oxygens.

Also notice that the left side of the equation has only even numbers of oxygens that are available. Right now there are 2, if you add a "2" coefficient in front of the O₂ there will be 4, if you add a 3 coefficient there will be 6, etc. But the right side of the equation has a single oxygen in the H₂O meaning that as it is, there will be an odd number of oxygens. That is never going to work because you can't balance the equation with an odd number on one side and an even on the other. So you MUST change the coefficient in front of the H₂O to be an even number. So double it and make it 6:

C₂H₆ + O₂ => 6H₂O + 2CO₂

that make 12 hydrogens on the right so put a "2" as the coefficient in front of the C₂H₆:

2C₂H₆ + O₂ => 6H₂O + 2CO₂

Now the hydrogens balance but the carbons do not. So change the coefficient in front of the CO₂ from 2 to 4:

2C₂H₆ + O₂ => 6H₂O + 4CO₂

Now the hydrogens and the carbons are balanced. But the right side has 6 + 8 = 14 oxygens. To get the same on the left, place a 7 as the coefficient in front of the O₂:

2C₂H₆ + 7O₂ => 6H₂O + 4CO₂

Now everything balances.