For Class 8, 9 & 10
Foundation - a strong base in Physics, Chemistry, Maths & Biology
Concept-first questions with clear model answers across all four subjects, aligned to NCERT. Start early, build the habit, and walk into your board exams, NEET and JEE already ahead.
Showing 1 question in Chemistry for Class 9. Tap a card to reveal the answer.
ChemistryAtoms and MoleculesmediumState the law of conservation of mass with an example.
Reveal answer ↓
What it is
In any chemical reaction the total mass stays the same - atoms are only rearranged, never lost.
Answer
The law of conservation of mass states that mass can neither be created nor destroyed in a chemical reaction; the total mass of the reactants equals the total mass of the products. For example, when 12 g of carbon burns completely in 32 g of oxygen, exactly 44 g of carbon dioxide is formed (12 + 32 = 44).
mass of reactants = mass of products
- •Mass is neither created nor destroyed
- •Total mass of reactants = total mass of products
- •Example: 12 g C + 32 g O2 -> 44 g CO2
Why learn this
It's why every chemical equation must be BALANCED - the foundation of all of chemistry.
💡 Memory trick
Atoms in = atoms out. Nothing vanishes, it just rearranges.