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.
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 do you mean by the term Volume?
Q 8.
What are the ways a gas can be liquefied?
Q 9.
Why solids cannot be compressed like gases?
Q 10.
Define the term Volatile Liquid.
Q 11.
Define transpiration.
Q 12.
Arrange the following substances in increasing order of intermolecular force of attraction: water, sugar, oxygen
Q 13.
Which state of matter is most easily compressible?
Q 15.
Define evaporation.
Q 16.
What are the differences between boiling and evaporation?
Q 17.
Our own bodies contain examples of all three states of matter. Can you identify these?
Q 18.
Why is light not considered matter?
Q 19.
What do you mean by the following terms:
a. Evaporation
b. Sublimation
c. Condensation
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.
How can matter change its state?
Q 22.
Define Latent Heat of Fusion and Latent Heat of vaporisation.
Q 23.
How matter is classified in terms of composition?
Q 24.
Why do gases diffuse rapidly?
Q 25.
Why do diffusion become faster at higher temperatures?
Q 26.
Which of the following state does not exist at room temperature conditions: a) Solids b) Liquids c) Gas d) Plasma
Q 27.
Convert the temperature of 373°C to the Kelvin scale.
Q 28.
What is the physical state of water at the following temperatures? (a) 25 °C (b) 0 °C (c) 100 °C
Q 29.
How vapour is different from gases? Give examples of each.
Q 30.
In which case evaporation of water will be faster i.e. near the sea or far away from the sea.
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.
Give the usual name for the following :Heat required to change the state of a substance without changing the temperature.
Q 34.
Why do solids expand a bit on heating and contract a bit on cooling?
Q 35.
What is the general name of : (a) rigid form of matter ? (b) fluid forms of matter ?
Q 36.
The Kelvin temperature is 270 K. What is the corresponding Celsius scale temperature ?
Q 37.
Write the full forms of the following :(a) LPG (b) CNG
Q 38.
Honey is more viscous than water. Can you suggest why ?
Q 39.
A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?
Q 40.
What causes evaporation?
OR
Explain evaporation and its cooling effect in terms of kinetic energy of particles.
Q 41.
What are the conditions for 'something' to be called 'matter' ?
Q 42.
Which of the following are matter?
Chair, Air, Love, Smell, Hate, Almonds, Thought, Cold, Cold drinks, Smell of perfume
Q 43.
Give reasons to justify: (a) Water at room temperature is a liquid. (b) An iron almirah is solid.
Q 44.
Why is ice at 273 K more effective in cooling than water at the same temperature?
Q 45.
The Kelvin scale temperature is 0 K. What is the corresponding Celsius scale temperature ?
Q 46.
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 47.
The boiling point of water is 100°C. Express this in SI units (Kelvin scale).
Q 48.
Convert the temperature of 573 K to the Celsius scale.
Q 49.
Why does the temperature of a substance remain constant during melting and boiling even when heat is being supplied to it continuously?
Q 50.
What is a dry ice and what are its properties?
