Balancing a chemical equation is an important skill in chemistry. It helps us follow the law of conservation of mass, which says that matter cannot be created or destroyed. Here’s how you can balance a chemical equation step by step:

Step-by-Step Instructions

1. Write the Unbalanced Equation: Start by writing down the basic equation using the right formulas for all the substances. For example: [ \text{C}_3\text{H}_8 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} ]

2. Count Atoms: List how many atoms are in each part (reactants and products). For the example above:

   • In the reactants: Carbon (C) = 3, Hydrogen (H) = 8, Oxygen (O) = 2
   • In the products: Carbon (C) = 1, Hydrogen (H) = 2, Oxygen (O) = 3

3. Balance One Element at a Time: Start with elements that are only in one reactant and one product. In this case, let’s balance the carbon first:

   • Change the equation to balance the carbon: [ \text{C}_3\text{H}_8 + \text{O}_2 \rightarrow 3\text{CO}_2 + \text{H}_2\text{O} ]

4. Continue Balancing Other Elements: Next, look at hydrogen:

   • Update the equation as needed: [ \text{C}_3\text{H}_8 + \text{O}_2 \rightarrow 3\text{CO}_2 + 4\text{H}_2\text{O} ]

5. Balance Oxygen Last: Count the total number of oxygen atoms in the products:

   • From 3 CO2, that gives us 6 oxygen (O) and from 4 H2O we get 4 oxygen. Together, that adds up to 10 oxygen atoms.

6. Adjust Coefficients for Oxygen: Update the equation based on this count: [ \text{C}_3\text{H}_8 + 5\text{O}_2 \rightarrow 3\text{CO}_2 + 4\text{H}_2\text{O} ]

7. Check Your Work: Finally, go back and recount all the atoms to make sure they match on both sides.

Key Points

• The law of conservation of mass says that you need the same number of atoms on both sides of the equation.
• The total number of atoms must be equal for the reactants and products.
• A balanced equation is important for accurate calculations in chemistry, whether in theory or in real-life situations.