# Question 1

Define Matter

Solution:
Matter may be defined as something that has mass and occupies space.

# Question 2

Give an account of the classification of matter.

Solution:
The important type of classification of matter is Homogeneous and Heterogenous materials.

Homogeneous materials are divided into two types:

(i) Homogeneous mixture (solutions)
(ii) Pure substances.
Pure substances are two types- elements and compounds.
Elements are classified as metals, non-metals and metalloids.

# Question 3

Define the term inter-conversion of matter.

Solution:
The phenomenon of change of one state of matter into another and back to the original state is called inter-conversion of matter.

# Question 4

What is meant by physical property of substance? Name the important physical property?

Solution:
Physical properties: Physical properties of a substance are those which are observed without altering the identity of the State .
• Colour
• Smell
• Density
• Solubility.
• Melting and boiling points.
• Thermal conductivity.
• Electrical conductivity.

# Question 5

When ink overflows from a fountain pen, we use blotting paper to remove excess of ink on the paper. Why?

Solution:
Because ink (liquid) diffuses into the blotting paper, we use blotting paper to remove excess of ink on the paper from a fountain pen.

# Question 6

Show that solids diffuse in water.

Solution:
Take about 250 ml of water in 500 ml beaker. With the help of a forceps place carefully a crystal of potassium permanganate at the bottom of the beaker without disturbing the water. Watch for some time. You will find that the violet or pink color of potassium permanganate gradually spreads in the water in the beaker, showing that solids also diffuse, but slowly.

# Question 7

Show that liquids also diffuse in water.

Solution:
Take about 250 ml of water in a 500 ml beaker. With the help of a dropper, add a drop of blue ink carefully to the bottom of the beaker. After some time the blue ink colour spreads in the water slowly. It shows that liquids also diffuse, but slowly.

# Question 8

Among gases and liquids which diffuse very fast?

Solution:
Gases diffuse very fast when compared to liquids.

# Question 9

What are the properties of gases?

Solution:
1. Gases can be compressed easily (into a small volume)
2. Gases have very low densities. They are very, very light.

# Question 10

Write a note on the uses of metals.

Solution:
Metals are used to make electric wires, cables, utensils, ornaments, coins, maufacture of aeroplanes, airships, thermometers, Barometers, drying agent for organic liquids, filament in electric bulbs and to prepare alloys.