Force and Laws of Motion — Science STD 9 — Question

State one property in which a solution of sugar in water resembles a mixture of sugar and sand, and one property in which it differs from it.

What valencies will be shown by the elements A, B, C, D and E having atomic numbers 2, 4, 8, 10, and 13 respectively.

A beaker full of water is suspended from a spring balance. Will the reading of the balance change:

1. If a cork is placed in water?
2. If a piece of heavy metal is placed in it?

Give reasons for your answer.

Define gram molecular mass of a substance. How much is the gram molecular mass of oxygen?

Which contains more heat, 1kg of ice at 0°C or 1kg of water at 0°C? Give reason for your answer.

Composition of the nuclei of two atomic species A and B is given as under:

	A	B
Protons	18	20
Neutrons	22	20

Give the mass numbers of A and B. What is the relation between the two species and which element or elements they represent?

On what factors does the gravitational potential energy of a body depend?

What is meant by the term ‘buoyancy’?

Give two reasons for supposing that water is a compound and not a mixture.