Balanced Chemical Equation MCQs Quiz | Class 10
Test your understanding of balancing chemical equations for Class X Science (Code 086), Unit I: Chemical Substances – Nature and Behaviour. This quiz covers balancing methods, correctness criteria, and the conservation of mass. Click ‘Submit Quiz’ to check your score and download the PDF answer sheet.
Mastering Balanced Chemical Equations
A balanced chemical equation occurs when the number of atoms for each element in the reaction and the total charge is the same for both the reactants and the products. This adheres to the Law of Conservation of Mass, which states that mass can neither be created nor destroyed in a chemical reaction.
Key Concepts in Balancing
- Law of Conservation of Mass: The total mass of elements present in the products of a chemical reaction has to be equal to the total mass of elements present in the reactants.
- Hit and Trial Method: The standard method used to balance equations by adjusting coefficients (the numbers before the formulas) to equate the number of atoms on both sides.
- Physical States: To make a chemical equation more informative, the physical states of the reactants and products are mentioned along with their chemical formulae (g for gas, l for liquid, s for solid, aq for aqueous).
Example of Balancing
Consider the reaction between Iron and Water:
Fe + H2O -> Fe3O4 + H2 (Unbalanced)
To balance this, we ensure the number of Fe, H, and O atoms are equal on both sides:
3Fe + 4H2O -> Fe3O4 + 4H2 (Balanced)
Quick Revision Points
| Component | Description |
|---|---|
| Reactants | Substances that undergo chemical change (Left side). |
| Products | New substances formed (Right side). |
| Coefficients | Whole numbers used to balance atoms. |
Extra Practice Questions
- Balance the equation: H2 + O2 -> H2O.
- What is the coefficient of CO2 in the combustion of Propane (C3H8)?
- Why can we not change the subscripts in a chemical formula while balancing?
- Write the balanced equation for Magnesium burning in Oxygen.
- Identify the physical state symbol for a solution in water.
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