Chemical equation and balancing of chemical equation

Chemical Equations and Balancing of Chemical Equations

What is a Chemical Equation?

A chemical equation describes a chemical reaction using symbols and formulas. It illustrates how the starting materials, known as reactants, are transformed into new substances called products.

Example:

When hydrogen reacts with oxygen to form water, it is written as:
H2 + O2 → H2O

This equation is called a skeleton chemical equation, because it is not yet balanced.

Why Do We Need to Balance a Chemical Equation?

According to the Law of Conservation of Mass, mass can neither be created nor destroyed during a chemical reaction. Therefore, the number of atoms of each element must be the same on both sides of the equation.

Steps to Balance a Chemical Equation

1. Write the unbalanced (skeleton) equation.
2. Count the atoms of each element on both the reactant and product sides of the equation.
3. Add coefficients (numbers) before chemical formulas to balance the atoms.
4. Ensure all elements are balanced and double-check your final equation.

Example of Balancing a Chemical Equation

Unbalanced equation:

Step 1: Count atoms on both sides:

• Left: H = 2, O = 2
• Right: H = 2, O = 1

Step 2: Balance oxygen by putting coefficient 2 before H₂O:

Now check hydrogen: Left = 2, Right = 4 (because 2H₂O has 4 H atoms).

Step 3: Balance hydrogen by putting 2 before H₂:

Balanced form of the equation: 2H₂ + O₂ → 2H₂O

Key Points

• Only coefficients (numbers before compounds) are changed to balance an equation.
• Subscripts (small numbers in formulas) should not be changed.
• Balanced equations follow the Law of Conservation of Mass.

It is important to balance chemical equations to accurately show what happens during a chemical reaction. It ensures that the same number of atoms for each element is present on both sides, maintaining the law of conservation of mass.