Science - Class 9

Q49. A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?

 

Q50. Liquids generally have lower density as compared to solids. But you must have observed that ice floats on water. Find out why?

 

Q51. Why is honey more viscous than water?

 

Q52. What is meant by ‘diffusion’? Give one example of diffusion in gases.

 

Q53. What does the diffusion of gases tell us about their particles?

 

Q54. When salt is dissolved in water, there is no increase in the volume. Which characteristic of matter is illustrated by this observation?

Or

Why does the level of water not change when salt is dissolved?

 

Q55. What is the physical state of water at: a. 250ºC b. 100ºC?

 

Q56. Why does the temperature remain constant during the melting of ice even though heat is supplied continuously?

Or

Why does temperature remain constant during melting of ice?

 

Q57. Which contains more heat energy, water at 100°C or steam at 100°C?

 

Q58. Name the three states of matter. Give one example of each.

 

Q59. Just a few crystals of potassium permanganate can colour a large volume of water (about 1000 L). Which characteristic of particles of matter is illustrated by this observation?

 

Q60. Why does the temperature remain constant during the boiling of water even though heat is supplied continuously?

Or

Why does temperature remain constant during boiling of water?