Contents
Key Stage 3
Meaning
A Balanced Symbol Equation is a way to show the reactants and products in a chemical reaction using the chemical formulae of the reactants and products.
About Balanced Symbol Equations
- Balanced Symbol Equations shows the number of molecules of each chemical and the numbers of each atom within those chemicals.
- Balanced Symbol Equations can be used to find the quantity of each chemical needed to have a complete chemical reaction.
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| This shows there are two H2 molecules and one O2 molecule needed to make two molecules of H2O. |
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| This shows there is one CH4 molecule and two O2 molecules needed to make one molecule of CO2 and two molecules of H2O. |
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| This shows there are two atoms of Mg and one molecule of O2 needed to make two molecules of MgO. |
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| This shows there are two HCl molecules and one Li2O molecule needed to make two molecules of LiCl and one molecule of H2O. |
Balancing Equations
- You may know the chemical formulae of the reactants and products but not know the number of each chemical needed. For that you must balance the equation.
- To balance and equation you need the same number of each type of atom on the left as you do on the right.
- _Li + _F2 → _LiF
- Reactants = Products
- 1Li = 1Li
- 2F ≠ 1F
We need 2 Fluorine atoms in the products.
- _Li + _F2 → 2LiF
- Reactants = Products
- 1Li ≠ 2Li
- 2F = 2F
There are now too many Lithium atoms in the products so we need 2 in the reactants.
- 2Li + _F2 → 2LiF
- Reactants = Products
- 2Li = 2Li
- 2F = 2F
This equation is balanced: 2Li + F2 → 2LiF