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Answer 1

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Answer 2

Answer:

Question 1.  

Answer: (a) 293 K into °C

293 – 273 = 20°C

(b) 470 K into °C 470 – 273 = 197°C

Question 2.  

Answer: (a) 25°C into K

25 + 273 = 298 K

(b) 373°C into K 4 373 + 273 = 646 K

 

Question 3.  

Answer: (a) Naphthalene balls disappear with time without leaving any solid, because naphthalene balls sublime and directly changes into vapour state without leaving any solid.

(b) We can get the smell of perfume sitting several metres away because perfume contain volatile solvent and diffuse faster and can reach people sitting several metres away.

Question 4.  

Answer: Oxygen —> water —> sugar.

Question 5.  

Answer: (a) 25°C is liquid (b) 0°C is solid or liquid

(c) 100°C is liquid and gas

Question 6.  

Answer: (a) Water at room temperature is a liquid because its freezing point is 0°C and boiling point is 100°C.

(b) An iron almirah is a solid at room temperature because the melting point of iron is higher than at room temperature.

Question 7.  

Answer: Ice at 273 K will absorb heat energy or latent heat from the medium to overcome the fusion to become water. Hence the cooling effect of ice is more than the water at the same temperature because water does not absorb this extra heat from the medium.

Question 8.  

Answer: Steam at 100°C will produce more severe bums as extra heat is hidden in it called latent heat whereas the boiling water does not have this hidden heat.

Question 9.  

Answer: A —> Liquefication/melting/fusion B —> Vapourisation/evaporation C—>Condensation D—> Solidification E —> Sublimation F —> Sublimation

Explanation: