Is Matter Around Us Pure? — Science STD 9 — Question

What is the significance of the formula of a substance?

How will you separate a mixture containing sand and sugar?

By which method of separation the volatile component from its non-volatile solute can be separated?

Why is it not possible to see an atom even with the most powerful microscope?

Write an activity to demonstrate balanced and unbalanced forces.

State an important characteristic of uniform circular motion. Name the force which brings about uniform circular motion.

State whether the following objects possess kinetic energy, potential energy, or both:

1. A man climbing a hill.
2. A flying aeroplane.
3. A bird running on the ground.
4. A ceiling fan in the off position.
5. A stretched spring lying on the ground.

Define the term ‘latent heat of fusion’ of a solid. How much is the latent heat of fusion of ice?

Which postulate of Dalton’s atomic theory can explain the law of conservation of mass?

The solubility of ammonium chloride in water at various temperatures is given below:

Temperature:	10°C	20°C	40°C	60°C	80°C
Solubility:	24g	37g	41g	55g	66g

What mass of ammonium chloride whould be needed to make a saturated solution of ammonium chloride in fifty grams of water at 40°C?