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 2 questions in Chemistry for Class 9. Tap a card to reveal the answer.
ChemistryIs Matter Around Us PuremediumGive two differences between a mixture and a compound.
Reveal answer ↓
What it is
A mixture is a physical blend you can separate; a compound is a fixed chemical union with new properties.
Answer
In a mixture the components are just mixed physically in any ratio, keep their own properties and can be separated by physical methods like filtration. In a compound the elements are chemically combined in a fixed ratio to form a new substance with new properties, and they can be separated only by chemical methods. For example, a mixture of iron and sulphur versus the compound iron sulphide.
- •Mixture: physical, any ratio, keeps properties, separated physically
- •Compound: chemical, fixed ratio, new properties, separated chemically
- •Example: iron+sulphur mix vs iron sulphide
Why learn this
It's how chemists tell air (mixture) from water (compound) and separate ores and medicines.
💡 Memory trick
Mixture = Mixed (any ratio, easy split); Compound = Chemically bonded (fixed, hard to split).
ChemistryIs Matter Around Us PuremediumWhat is the Tyndall effect, and what does it tell us about a mixture?
Reveal answer ↓
What it is
The Tyndall effect is light scattering off colloid particles, revealing the beam's path.
Answer
The Tyndall effect is the scattering of a beam of light by the tiny particles of a colloid, which makes the path of the light visible. It shows that the mixture is a colloid (like milk or fog), because a true solution's particles are too small to scatter light while a colloid's particles are just the right size.
- •Scattering of light by colloidal particles makes the beam visible
- •Seen in colloids (milk, fog), not in true solutions
- •Shows the particle size is in the colloidal range
Why learn this
It's why you see sunbeams through fog or a projector beam in a dusty room.
💡 Memory trick
If you can SEE the light beam, it's a colloid (Tyndall). Crystal-clear = true solution.