Exercise
1. Convert the following temperatures to the celsius scale.
(a) 293 K
(b) 470 K
2. Convert the following temperatures to the Kelvin scale.
(a) 25°C
(b) 373°C
3. Give reason for the following observations.
(a) Naphthalene balls disappear with time without leaving am
solid.
(b) We can get the smell of perfume sitting several metres away
4. Arrange the following substances in increasing order of forces
of attraction between the particles-water, sugar, oxygen.
What in t
Answers
Answer:
293k (b) we can get the smell of perfume
Answer:
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Explanation:
1. As we know 0° C =273.16 K. For convenience, we take 0° C = 273 K after rounding off the decimal.
To change a temperature on the Kelvin scale to the Celsius scale we have to subtract 273 from the given temperature
(a) 293 K = 293-273 = 20° C
(b) 470 K = 470-273 = 197° C
2. Answer : Kelvin is the SI unit of temperature, 0° C =273.16 K. For convenience, we take 0° C = 273 K
after rounding off the decimal. To convert a temperature on the Celsius scale to the Kelvin scale we have to add 273 to the given temperature.
(a) 25°C = 25 + 273 = 298 K
(b) 373°C = 373 + 273 = 646 K
3. (a) Naphthalene balls disappear with time without leaving any solid. This is due to the property of sublimation. Some solids do not exist in their liquid form or changes from solid to liquid; instead they directly evaporate from their solid form to vapour forms. Naphthalene is a sublime substance with very high vapors pressure, that show the property of sublimation. So naphthalene balls disappear after some time due to the property of sublimation.
(b) We can get the smell of perfume sitting several metres away. This is due to high rate of diffusion of perfume particles. Liquid generally vaporize at normal temperature. Perfume particles on vaporizing, intermix on their own with each other and air molecules around at a very fast rate. They do so by getting into the spaces between the particles. This intermixing of particles of two different types of matter on their own is called diffusion.Therefor the smell of perfume reach us sitting metres away.
4. Substances in increasing order of forces of attraction between the particles.
. Oxygen
. Water
. Sugar