Question:
Define the following terms:
a. Melting point
b. Freezing point
c. Boiling point
Answer:
a. The temperature at which solid changes into liquid is called its melting point. b. The temperature at which liquid changes into solid. c. The temperature at which liquid changes into vapors is termed as its boiling point.
Matter in Our Surroundings
Q 1.
What is SI unit of temperature? Give mathematical relation also.
Q 3.
What do you mean by change in state?
Q 4.
How matter is classified in terms of physical state?
Q 5.
What is evaporation? Why does evaporation cause cooling?
Q 6.
What do you mean by the term Volume?
Q 7.
Which state of matter is most easily compressible?
Q 8.
List any five physical properties of liquids.
Q 9.
What are the ways a gas can be liquefied?
Q 10.
Define the term Volatile Liquid.
Q 11.
Arrange the following substances in increasing order of intermolecular force of attraction: water, sugar, oxygen
Q 12.
Define transpiration.
Q 14.
Why solids cannot be compressed like gases?
Q 15.
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 16.
How matter is classified in terms of composition?
Q 17.
Define evaporation.
Q 18.
What are the differences between boiling and evaporation?
Q 19.
Our own bodies contain examples of all three states of matter. Can you identify these?
Q 20.
What do you mean by the following terms:
a. Evaporation
b. Sublimation
c. Condensation
Q 21.
Define Latent Heat of Fusion and Latent Heat of vaporisation.
Q 22.
Why do diffusion become faster at higher temperatures?
Q 23.
Why is light not considered matter?
Q 24.
How can matter change its state?
Q 25.
How vapour is different from gases? Give examples of each.
Q 26.
Which of the following are matter?
Chair, Air, Love, Smell, Hate, Almonds, Thought, Cold, Cold drinks, Smell of perfume
Q 27.
What is the physical state of water at the following temperatures? (a) 25 °C (b) 0 °C (c) 100 °C
Q 28.
In which case evaporation of water will be faster i.e. near the sea or far away from the sea.
Q 29.
Convert the following temperature to Celsius scale: (a) 300 K (b) 573 K
Q 30.
Explain compressibility in gases with an example?
Q 31.
Why does the temperature of a substance remain constant during melting and boiling even when heat is being supplied to it continuously?
Q 32.
Which of the following state does not exist at room temperature conditions: a) Solids b) Liquids c) Gas d) Plasma
Q 33.
Why do gases diffuse rapidly?
Q 34.
Define the following terms:
a. Melting point
b. Freezing point
c. Boiling point
Q 35.
The Kelvin scale temperature is 0 K. What is the corresponding Celsius scale temperature ?
Q 36.
What factors affect the rate of evaporation?
Q 37.
Differences among solids, liquids and gases.
Q 38.
Explain with an experiment to show gases do not have fixed shape or volume.
Q 39.
Why is ice at 273 K more effective in cooling than water at the same temperature?
Q 40.
What is the scientific name of particles which make up matter ?
Q 41.
Name the process by which a drop of ink spreads in a beaker of water.
Q 42.
What are the characteristics of matter?
Q 43.
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 44.
What are the conditions for 'something' to be called 'matter' ?
Q 45.
What is the (a) common unit of temperature, and (b) SI unit of temperature ?
Q 46.
Write the relation between Kelvin scale and Celsius scale of temperature.
Q 47.
(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 48.
Give reasons to justify: (a) Water at room temperature is a liquid. (b) An iron almirah is solid.
Q 49.
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 50.
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.
