Overview: In this tutorial, the fundamentals of balancing chemical reactions are reviewed.
You are watching: What is the importance of the coefficients in a balanced chemical reaction?
You are watching: What is the importance of the coefficients in a balanced chemical reaction
Skills: Balancing Chemical Equations
New terms: Stoichiometry Stoichiometric CoefficientsIn civicpride-kusatsu.net it is very important to understand the relationship between reactants and products in a reaction. Stoichiometry is exactly that. It is the quantitative relation between the number of moles (and therefore mass) of various products and reactants in a chemical reaction. Chemical reactions must be balanced, or in other words, must have the same number of various atoms in the products as in the reactants.
If a chemical reaction is not balanced, no information about the relationship between products and reactants can be derived. So the first thing to do when you see a chemical reaction is to balance it. We balance reactions by adding coefficients in front of the reactants and products. These coefficients are the stoichiometric coefficients.General Guidelines for Balancing Simple EquationsAssign a "1" as the coefficient for the most complex species (the one whose chemical formula has the greatest number of different elements). Balance any single-element species last.Eliminate fractional coefficients (although this is not necessary).Add coefficients only; do not change the chemical formulas. There must be the same number of atoms on the left and right sides of the chemical reaction.These are just guidelines, not rules. Therefore, sometimes it may be necessary to deviate from these general guidelines.Example 1.
Balance the chemical reaction.
This equation is not balanced since there are more N and O atoms on the left side of the equation. Let"s start by using the guidelines. Assign a stoichiometric coefficient of 1 to the most complex compound, NO.
Now we can balance the remaining single-element compounds. In order to do this we will need to use fractional coefficients.
|Note: Typically a stoichiometric coefficient of "1" is not explicitly included when writing the chemical equation.|
We can get rid of the fractional coefficients by multiplying by 2 even though this is a perfectly acceptable balanced chemical equation.
|(Balanced, but without fractional coefficients)|
At the very beginning of this problem, perhaps you could see this was the answer. If you can see the balanced equation by sight, you don"t need to go by the guidelines. Remember they are only guidelines to help if you run into trouble. You can see by simply adding a 2 in front of NO, we violate the first guideline even though it leads us to a balanced equation.Example 2.Balance the given chemical reaction.
This one may not be as easy to see the final answer so we will use the guidelines to balance the equation. N2O3 is the most complex species so we will add a 1 for its coefficient.
Now we can balance the remaining single element species. In order to balance the number of atoms we need 2 atoms of N and 3 atoms of oxygen on the left side of the equation. There are already 2 atoms of N so we can add 3/2 in front of oxygen to get 3 atoms of oxygen.
|(Balanced, without fractional coefficients)|
We will balance the oxygen last because it is contained in a single-element species (O2). This means we need to balance the C and H atoms next. So we need 6 atoms of C and 12 atoms of H on the right side of the reaction.
See more: What Is The Chemical Formula For Lithium Oxide ? Lithium Oxide
So now we have 6 atoms of C and 6 atoms of H2 (which accounts for twelve H atoms). Now we can balance the oxygen. We have a total of 18 oxygen atoms on the right side. In order to have 18 atoms of oxygen on the left side we will need to assign a 6 to O2.