What is the Difference Between Balanced and Unbalanced Equation

The main difference between balanced and unbalanced equation is that in a balanced chemical equation, the number of atoms of each element is the same on both sides of the equation (the reactants and the products), whereas in an unbalanced chemical equation, the number of atoms of each element is not the same on both sides of the equation.

Balanced and unbalanced equations are fundamental concepts in chemistry, defining how chemical reactions work.

Key Areas Covered

1. What is a Balanced Equation
      – Definition, Feature, How to Balance an Equation
2. What is an Unbalanced Equation
      – Definition, Features 
3. Similarities Between Balanced and Unbalanced Equation
      – Outline of Common Features
4. Difference Between Balanced and Unbalanced Equation
      – Comparison of Key Differences
5. FAQ: Balanced and Unbalanced Equation
      – Frequently Asked Questions

Key Terms

Balanced Equation, Unbalanced Equation

What is a Balanced Equation

A balanced equation, in the context of chemistry, is a representation of a chemical reaction where the number of atoms of each element on the reactant side of the equation is equal to the number of atoms of the same element on the product side of the equation. In other words, a balanced equation follows the law of conservation of mass, which states that matter cannot be created or destroyed during a chemical reaction; it can only be rearranged.

Consider a simple example: the combustion of methane (CH4) in oxygen (O2) to produce carbon dioxide (CO2) and water (H2O). The balanced equation for this reaction is:

CH₄ + 2O₂ -> CO₂ + 2H₂O

In this equation, the number of carbon (C) atoms, hydrogen (H) atoms, and oxygen (O) atoms is the same on both sides. This balancing ensures that no atoms are created or destroyed during the reaction; they are merely rearranged into new molecules.

Balancing chemical equations is a skill that all chemistry students must master. It involves adjusting the coefficients (the numbers in front of chemical formulas) so that the number of each type of atom is equal on both sides of the equation. The following steps can help you balance chemical equations:

How to Balance an Equation

1. List the Reactants and Products: Start by writing down the chemical formulas for the reactants and products. Ensure you have the correct formulas and know the correct state of matter (solid, liquid, gas, or aqueous) for each substance.
2. Count the Atoms: Count the number of each type of atom on both sides of the equation. A tally can be helpful. Pay attention to subscripts and coefficients.
3. Balance the Most Complex Compounds First: Begin by adjusting the coefficients of the most complex compounds first. These are usually compounds with the most elements or atoms. Often, you may need to balance oxygen (O) and hydrogen (H) atoms last, as they frequently appear in multiple compounds.
4. Use Coefficients to Equalize the Atoms: To balance the equation, change the coefficients in front of the compounds. You can’t change subscripts, as they represent the number of atoms in a molecule. Make sure that the number of each type of atom is the same on both sides of the equation.
5. Recalculate and Refine: After changing coefficients, recheck the number of atoms for each element. If they are not equal on both sides, refine your coefficients until they reach a balance.
6. Adjust Redox Reactions (if necessary): In some cases, chemical reactions involve electron transfer, known as redox reactions. These reactions require additional steps to balance the charge and the number of electrons transferred.
7. Check the Final Equation: Verify that all atoms are balanced and that the equation follows the law of conservation of mass.
8. Consider Whole Number Coefficients: Always use whole number coefficients to represent the smallest whole number ratio of reactants and products. Fractional coefficients should be avoided.

What is an Unbalanced Equation

An unbalanced equation is a representation of a chemical reaction where the number of atoms of each element on the reactant side of the equation is not equal to the number of atoms of the same element on the product side of the equation. In other words, the equation does not follow the law of conservation of mass, which asserts that matter cannot be created or destroyed during a chemical reaction. Moreover, unbalanced equations imply that the amount of matter is not conserved; it appears to be created or destroyed.

Let’s consider a simple example: the combustion of methane (CH₄) in oxygen (O₂) to produce carbon dioxide (CO₂) and water (H₂O). An unbalanced equation for this reaction might look like this:

CH₄ + O₂ -> CO₂ + H₂O

In this equation, the number of carbon (C) atoms, hydrogen (H) atoms, and oxygen (O) atoms is not the same on both sides. This imbalance suggests that, according to the equation, we start with one carbon atom and end up with only one carbon atom, which is not accurate. It also implies the creation of one oxygen atom and the disappearance of two hydrogen atoms, which is not consistent with the conservation of mass.

Similarities Between Balanced and Unbalanced Equations

• Both balanced and unbalanced equations help to represent chemical reactions.
• They use chemical formulas to represent the reactants and products.

Difference Between Balanced and Unbalanced Equation

Definition

In a balanced equation, the number of atoms of each element on the reactant side of the equation is equal to the number of atoms of the same element on the product side of the equation. However, in an unbalanced equation, the number of atoms of each element on the reactant side is not equal to the number of atoms on the product side.

Coefficients

Balanced equations have coefficients (the numbers in front of chemical formulas) that are carefully adjusted to ensure that the number of each type of atom is the same on both sides of the equation. Unbalanced equations may have coefficients, but these coefficients are not adjusted to ensure that the equation follows the conservation of mass.

Use

Balanced equations are necessary for performing mathematical calculations, while unbalanced equations are not suitable for performing accurate mathematical calculations.

FAQ: Balanced and Unbalanced Equations

What makes an equation balanced or unbalanced?

• An equation is balanced when the number of atoms of each element on the reactant side is equal to the number of atoms of the same element on the product side. An equation is unbalanced when these atom counts are not equal.

Why is an unbalanced equation a problem?

• An unbalanced equation is a problem because it violates the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. This means that the number of atoms on the reactant side must be equal to the number on the product side.

What are unbalanced equations called?

• Unbalanced equations are called skeletal equations.

Conclusion

In a balanced chemical equation, the number of atoms of each element is the same on both sides of the equation. However, in an unbalanced chemical equation, the number of atoms of each element is not the same on both sides of the equation. Thus, this is the main difference between balanced and unbalanced equation.

Reference:

1. “Balancing-chemical-equations” Byju’s.

Image Courtesy:

1. “Combustion of propane – balancing chemical reaction” By Kvr.lohith – Own work (CC BY-SA 4.0) via Commons Wikimedia