30. Explain why, we can easily move our hand in air but to do the same through a plank of wood, we need a karate expert? 31. Give one example of the diffusion of a solid in another solid
32 Explain why, the diffusion of a solid in another solid is a very slow proces
33. Which of the following diffuses fastest and which the slowest ?
Solid, Liquid, Gas
Give reasons for your answer.
34 Explain the following:
When an incense stick is lighted in the comer of a room, its fragrance spreads quickly in the entire room
35. Name the three states of matter. Give one example of each
36. State two characteristic properties each of
(a) a solid
(b) a liquid
(c) a gas
37. Why do gases have neither a fixed shape nor a fixed volume ?
38. How do solids, liquids and gases differ in shape and volume ?
39. Arrange the following substances in increasing order of force of attraction between their particles (keeping
the substance having the minimum force of attraction first):
Water, Sugar, Oxygen?
please answer it fast