Matter in Our Surrounding

Matter in our surrounding Worksheet-4

31. The smell of hot sizzling food reaches us several metres away. However, it is not so in case the food is cold. Explain.

A. kinetic energy of the particles released by hot food is very high in the vapour state

B. kinetic energy of the particles released by cold food is very high in the vapour state

C. Vapours are not released by cold food where as vapours are released by hot food

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

A. There is very less force of attraction between the particles of water

B. Particles of water are scattered as there is large intermolecular space between them

Matter in our surrounding Worksheet-5

1. Why does steam produce more severe burns on the skin as compared to boiling water?

2. Carbon dioxide gas is heavier than both nitrogen and oxygen. Why it does not form lower layer in the atmosphere?

3. Ammonia and hydrogen chloride gases are both pungent smelling in nature. These are released from the two opposite corners in a room. Which gas will first reach a person sitting in the centre of the room?

4. Solids are normally not compressible. Why a sponge can be readily pressed?

5. Why is it not proper to regard the gaseous state of ammonia as vapours?

Matter in our surrounding Worksheet-6

11. Are the melting point temperature of the solid state and the freezing point temperature of the liquid state of a substance different?

12. A substance is in liquid state at room temperature and changes into gas upon heating. What will you call its gaseous state?

13. When a crystal of copper sulphate is placed at the bottom of a beaker containing water, the colour of water slowly becomes blue, why ?

14. The boiling point of ethyl alcohol is 78°C. What is the corresponding temperature on kelvin scale?

15. Does the evaporation of a liquid occur only at a fixed temperature?