Question:
How vapour is different from gases? Give examples of each.
Answer:
In general, those substances which are liquids at room temperature and turn into gas state due to evaporation are called vapours. While the substances which are in gaseous state at room temperature are termed as 'gases'. e.g. Sulphur, camphor exhibit phase change and turn into vapours. While Carbon Dioxide (CO2), Oxygen (CO2), Nitrogen (N2), Helium (He) exist as gases at room temperatures.
Matter in Our Surroundings
Q 1.
What is SI unit of temperature? Give mathematical relation also.
Q 2.
How matter is classified in terms of physical state?
Q 4.
What do you mean by change in state?
Q 5.
List any five physical properties of liquids.
Q 6.
What is evaporation? Why does evaporation cause cooling?
Q 7.
What are the ways a gas can be liquefied?
Q 8.
What do you mean by the term Volume?
Q 9.
Which state of matter is most easily compressible?
Q 10.
Why solids cannot be compressed like gases?
Q 11.
Define the term Volatile Liquid.
Q 12.
Define transpiration.
Q 13.
Arrange the following substances in increasing order of intermolecular force of attraction: water, sugar, oxygen
Q 15.
Define evaporation.
Q 16.
What are the differences between boiling and evaporation?
Q 17.
What do you mean by the following terms:
a. Evaporation
b. Sublimation
c. Condensation
Q 18.
Our own bodies contain examples of all three states of matter. Can you identify these?
Q 19.
Define Latent Heat of Fusion and Latent Heat of vaporisation.
Q 20.
The mass per unit volume of a substance is called density (density=mass/volume). Arrange the following in order of increasing density:
Air, Exhaust from chimneys, Honey, Water, Chalk, Cotton and Iron.
Q 21.
Why is light not considered matter?
Q 22.
How can matter change its state?
Q 23.
How matter is classified in terms of composition?
Q 24.
Why do diffusion become faster at higher temperatures?
Q 25.
Why do gases diffuse rapidly?
Q 26.
What is the physical state of water at the following temperatures? (a) 25 °C (b) 0 °C (c) 100 °C
Q 27.
Which of the following state does not exist at room temperature conditions: a) Solids b) Liquids c) Gas d) Plasma
Q 28.
How vapour is different from gases? Give examples of each.
Q 29.
In which case evaporation of water will be faster i.e. near the sea or far away from the sea.
Q 30.
Convert the temperature of 373°C to the Kelvin scale.
Q 31.
Name the process by which a drop of ink spreads in a beaker of water.
Q 32.
What is the (a) common unit of temperature, and (b) SI unit of temperature ?
Q 33.
What causes evaporation?
OR
Explain evaporation and its cooling effect in terms of kinetic energy of particles.
Q 34.
The Kelvin temperature is 270 K. What is the corresponding Celsius scale temperature ?
Q 35.
Which of the following are matter?
Chair, Air, Love, Smell, Hate, Almonds, Thought, Cold, Cold drinks, Smell of perfume
Q 36.
Why do solids expand a bit on heating and contract a bit on cooling?
Q 37.
Why does the temperature of a substance remain constant during melting and boiling even when heat is being supplied to it continuously?
Q 38.
Write the full forms of the following :(a) LPG (b) CNG
Q 39.
The Kelvin scale temperature is 0 K. What is the corresponding Celsius scale temperature ?
Q 40.
Give the usual name for the following :Heat required to change the state of a substance without changing the temperature.
Q 41.
Convert the following temperatures:
a. -78.0 °C to Kelvins
b. 775 K to °C
c. 489 K to °C
d. 24 °C to kelvins
Q 42.
(a) Define the term 'latent heat of vaporisation' of a liquid. What is the value of the latent heat of vaporisation of water ?
(b) Draw a labelled diagram of the experimental set-up to study the latent heat of vaporisation of water.
Q 43.
Convert the following temperature to Celsius scale: (a) 300 K (b) 573 K
Q 44.
What is the general name of : (a) rigid form of matter ? (b) fluid forms of matter ?
Q 45.
Convert the temperature of 573 K to the Celsius scale.
Q 46.
Is smell of garlic or perfume a matter?
Q 47.
The mass per unit volume of a substance is called density.(density = mass/volume). Arrange the following in order of increasing density – air, exhaust from chimneys, honey, water, chalk, cotton and iron.
Q 48.
Give reasons for the following observations. The smell of hot sizzling food reaches you several meters away, but to get smell from cold food you have to go close.
Q 49.
A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?
Q 50.
Give reasons to justify: (a) Water at room temperature is a liquid. (b) An iron almirah is solid.
