What is chemical equation?
The symbolic representation of a chemical reaction with formulae and symbols, where the reactant components are represented on the left-hand side and the product components are represented on the right-hand side is called a
chemical equation. The absolute values of the stoichiometric numbers are the coefficients next to the formulae of components or the symbols. Jean Beguin was the first to illustrate the chemical equation in the year 1615.
Common symbols used
To represent the type of chemical reaction the following symbols are used:
| Sl. no. | Symbol | Reaction type |
| 1. | = | Stoichiometric relation |
| 2. | → | Net forward reaction |
| 3. | ⇆ | Reaction in both directions |
| 4. | ⇌ | Equilibrium |
The state of chemicals is written in parentheses after the chemical symbol.
| Sl. no. | Alphabet | Physical state |
| 1. | s | Solid |
| 2. | l | Liquid |
| 3. | g | Gas |
| 4. | aq | Aqueous solution |
How to balance chemical equations?
The traditional method of balancing chemical equations is explained with an example:
Step 1: Write the given equation.
| Chemical Equation |
| C3H8 + O2 → H2O + CO2 |
Step 2: Write the number of atoms in each element.
Chemical Equation | |
C3H8 + O2 → H2O + CO2 | |
| Left-hand side | Right-hand side |
| C = 3 | C = 1 |
| H = 8 | H = 2 |
| O = 2 | O = 3 |
Step 3: Keep oxygen and hydrogen at the end, they occur on both sides.
Step 4: Begin with a single element.
| Chemical Equation | |
| C3H8 + O2 → H2O + CO2 | |
| Left-hand side | Right-hand side |
| C = 3 | C = 1 |
| H = 8 | H = 2 |
| O = 2 | O = 3 |
Step 5: To balance a single carbon atom, use the coefficient.
| Chemical Equation | |
| C3H8 + O2 → H2O + 3CO2 | |
| Left-hand side | Right-hand side |
| C = 3 | C = 13 |
| H = 8 | H = 2 |
| O = 2 | O = 3 7 |
Step 6: In this step balance the hydrogen atom.
You can alter the coefficients but should not change the subscripts.
| Chemical Equation | |
| C3H8 + O2 →4H2O + 3CO2 | |
| Left-hand side | Right-hand side |
| C = 3 | C = 13 |
| H = 8 | H = 28 |
| O = 2 | O = 3710 |
Step 7: After balancing the hydrogen atom, balance the oxygen atom.
| Chemical Equation | |
| C3H8 + 5O2 →4H2O + 3CO2 | |
| Left-hand side | Right-hand side |
| C = 3 | C = 13 |
| H = 8 | H = 28 |
| O = 210 | O = 3710 |
Therefore the balanced chemical equation is:
| Chemical Equation | |
| C3H8 + 5O2 →4H2O + 3CO2 | |
| Left-hand side | Right-hand side |
| C = 3 | C = 3 |
| H = 8 | H = 8 |
| O = 10 | O = 10 |
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