Introduction: How to Balance a Chemical Equation
A chemical equation is the chemical formula that provides the information of the elements and molecules that are reacting as well as the molecules that are being produced from that reaction. The Law of Conservation of Mass states that the mass of the reactants must balance the mass of the products. To balance a chemical equation, the atoms of both the elements and molecules on the reactant side (left side) and product side (right side) must be equal to each other.
In this instructable, you will understand and learn how to balance a chemical equation.
This instructable should take no longer than ten minutes.
Step 1: The Unbalanced Chemical Equation
The unbalanced chemical equation is given to you.
Aluminum reacts with oxygen to produce aluminum oxide.
Rewrite the equation as shown above.
Step 2: Make a List
First, identify the elements on the reactant side(left side) and the elements of the compound are on the product side (right side).
- make a list of all of the elements on each side under the equation for both the reactants and products as shown above
- Under the reactant’s side, list Al and O
- under the product’s side, list Al and O
Step 3: Identifying the Atoms in Each Element
An atom is the smallest component of an element that contains chemical properties of that element. The atom of each element’s contains the protons, neutrons, and electrons of that element.
The list made of each element on both the reactant and product side will further help you identify the number of atoms each element contains.
Next to each element of the list, put the number of atoms that are in each of the elements.
- on the reactants side, next to Al, put 1
- next to O, put 2
- apply these same rules to each element on the product side
Step 4: Multiplying the Number of Atoms
Notice how the number of atoms next to each element is different from the number of atoms next to that same element on the product side.
In order to balance the chemical equation, you need to make sure the number of atoms of each element on the reactant side is equal to the number of atoms of each element on the product side. In order make both sides equal, you will need to multiply the number of atoms in each element until both sides are equal.
As shown above, the multiplication of the atoms on the reactant side will affect both elements on the product side.
Step 5: Placing Coefficients in Front of Molecules
After you have multiplied the number of atoms of each element until both sides are equal, you will put the number, the coefficient, of how much you multiplied the element by and place in front of that element or compound in the equation as shown above.
- On the product side, although both elements did not get multiplied, still place the number that was multiplied as the coefficient in front of the compound.
Step 6: Check Equation
After you have placed the coefficients in front of the molecules, make the list of elements again and check to see if multiplying the coefficient with the subscript will give you atoms equal on both the reactant and product sides.
If they are not equal, rework your multiplication.
Step 7: Balanced Chemical Equation
After you have reworked your multiplication, make the list of elements again to check to make sure the equation is balanced. If both sides are equal, you have now balanced the chemical equation!