What are Balanced and Unbalanced Chemical Equations?
A chemical equation represents a chemical reaction where reactants transform into products. The equation must follow the Law of Conservation of Mass, which states that mass can neither be created nor destroyed in a chemical reaction.
Balanced Chemical Equation
✔ A chemical equation is balanced when the number of atoms of each element in the reactants is equal to the number of atoms of the same elements in the products.
Example:
2H₂ + O₂ → 2H₂O
✔ Here, the number of hydrogen and oxygen atoms are equal on both sides.
Unbalanced Chemical Equation
✔ A chemical equation is unbalanced when the number of atoms of each element in the reactants does not match the number of atoms of the same elements in the products.
Example:
H₂ + O₂ → H₂O
✔ Here, there are two oxygen atoms on the reactant side but only one on the product side, making it unbalanced.
Why is it Important to Balance Chemical Equations?
✔ Ensures the Law of Conservation of Mass is followed.
✔ Helps in determining the correct stoichiometric ratios of reactants and products.
✔ Provides accurate information for chemical reactions used in industries and laboratories.
Steps to Balance a Chemical Equation
1. Write the unbalanced equation.
2. Count the number of atoms of each element on both sides.
3. Use coefficients to balance the number of atoms.
4. Ensure that the total mass of reactants and products is the same.
Multiple Choice Questions on Balanced and Unbalanced Equations
Balanced vs. Unbalanced Equations – Test Your Knowledge with MCQs
- What is a balanced chemical equation?
- A) An equation with an unequal number of atoms on both sides
- B) An equation where the number of atoms of each element is equal on both sides
- C) An equation that involves only gases
- D) An equation that does not follow any rules
Answer: B) An equation where the number of atoms of each element is equal on both sides
- Which of the following represents a balanced equation?
- A) H₂ + O₂ → H₂O
- B) 2H₂ + O₂ → 2H₂O
- C) Na + Cl₂ → NaCl
- D) Fe + O₂ → Fe₂O₃
Answer: B) 2H₂ + O₂ → 2H₂O
- Why must chemical equations be balanced?
- A) To satisfy the Law of Conservation of Energy
- B) To satisfy the Law of Conservation of Mass
- C) To satisfy the Law of Gravity
- D) To satisfy the Law of Motion
Answer: B) To satisfy the Law of Conservation of Mass
- Which of the following is an example of an unbalanced equation?
- A) C + O₂ → CO₂
- B) 2Mg + O₂ → 2MgO
- C) H₂ + O₂ → H₂O
- D) N₂ + 3H₂ → 2NH₃
Answer: C) H₂ + O₂ → H₂O
- What does the coefficient in a balanced chemical equation represent?
- A) The mass of an element
- B) The ratio of reactants and products
- C) The speed of the reaction
- D) The pressure required
Answer: B) The ratio of reactants and products
- Which law states that mass cannot be created or destroyed in a chemical reaction?
- A) Law of Conservation of Energy
- B) Law of Conservation of Mass
- C) Law of Conservation of Motion
- D) Law of Conservation of Atoms
Answer: B) Law of Conservation of Mass
- If the unbalanced equation is Fe + O₂ → Fe₂O₃, what is the balanced equation?
- A) Fe + O₂ → Fe₂O₃
- B) 4Fe + 3O₂ → 2Fe₂O₃
- C) 2Fe + O₂ → Fe₂O₃
- D) Fe₂ + O₂ → FeO
Answer: B) 4Fe + 3O₂ → 2Fe₂O₃
- What is the first step in balancing a chemical equation?
- A) Counting the number of atoms of each element
- B) Adding coefficients randomly
- C) Writing only the products
- D) Removing extra elements
Answer: A) Counting the number of atoms of each element