easiest way to balance an equation
Answers
umber of atoms per element. Do this for each side of the equation. Look at the subscripts next to each atom to find the number of atoms in the equation. When writing it out, it's a good idea to connect it back to the original equation, noting how each element appears.[2]
For example, you have 3 oxygen atoms on the right side, but that total results from addition.
Left side: 3 carbon (C3), 8 hydrogen (H8) and 2 oxygen (O2).
Right side: 1 carbon (C), 2 hydrogen (H2) and 3 oxygen (O + O2).
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Save hydrogen and oxygen for last, as they are often on both sides. Hydrogen and oxygen are both common in molecules, so it's likely that you'll have them on both sides of your equation. It's best to balance them last.[3]
You'll need to recount your atoms before balancing the hydrogen and oxygen, as you'll likely need to use coefficients to balance the other atoms in the equation.
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Start with single elements. If you have more than one element left to balance, select the element that appears in only a single molecule of reactants and in only a single molecule of products. This means that you will need to balance the carbon atoms first.[4]
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Use a coefficient to balance the single carbon atom. Add a coefficient to the single carbon atom on the right of the equation to balance it with the 3 carbon atoms on the left of the equation.[5]
C3H8 + O2 --> H2O + 3CO2
The coefficient 3 in front of carbon on the right side indicates 3 carbon atoms just as the subscript 3 on the left side indicates 3 carbon atoms.
In a chemical equation, you can change coefficients, but you must never alter the subscript
Balance the hydrogen atoms next. Since you have balanced all atoms besides the hydrogen and oxygen, you can address the hydrogen atoms. You have 8 on the left side. So you'll need 8 on the right side. Use a coefficient to achieve this.[6]
C3H8 + O2 --> 4H2O + 3CO2
On the right side, you now added a 4 as the coefficient because the subscript showed that you already had 2 hydrogen atoms.
When you multiply the coefficient 4 times by the subscript 2, you end up with 8.
The other 6 atoms of oxygen come from 3CO2.(3x2=6 atoms of oxygen+ the other 4=10)