Question:
Give reasons to justify: (a) Water at room temperature is a liquid. (b) An iron almirah is solid.
Answer:
(a) Water is a liquid at room temperature:
- In water, the intermolecular forces are strong enough to keep its particles bound to each other.
- The melting point of water is below room temperature(so it does not convert into ice).
- Its boiling point is above room temperature (therefore it does not vaporise completely).
(b) An iron almirah is solid
- It has fixed shape and definite volume because of strong molecular cohesive forces.
- It is rigid and cannot be deformed easily because of strong molecular forces.
Matter in Our Surroundings
Q 2.
What do you mean by change in state?
Q 3.
Why is light not considered matter?
Q 4.
What is SI unit of temperature? Give mathematical relation also.
Q 5.
Define transpiration.
Q 6.
What is evaporation? Why does evaporation cause cooling?
Q 7.
Which of the following are matter?
Chair, Air, Love, Smell, Hate, Almonds, Thought, Cold, Cold drinks, Smell of perfume
Q 8.
Define the term Volatile Liquid.
Q 9.
Which state of matter is most easily compressible?
Q 10.
How matter is classified in terms of physical state?
Q 12.
How can matter change its state?
Q 13.
What are the ways a gas can be liquefied?
Q 14.
What do you mean by the following terms:
a. Evaporation
b. Sublimation
c. Condensation
Q 15.
What do you mean by the term Volume?
Q 16.
Define Latent Heat of Fusion and Latent Heat of vaporisation.
Q 17.
List any five physical properties of liquids.
Q 18.
Our own bodies contain examples of all three states of matter. Can you identify these?
Q 19.
Arrange the following substances in increasing order of intermolecular force of attraction: water, sugar, oxygen
Q 20.
What are the differences between boiling and evaporation?
Q 21.
Why solids cannot be compressed like gases?
Q 22.
Explain compressibility in gases with an example?
Q 23.
Define evaporation.
Q 24.
How matter is classified in terms of composition?
Q 25.
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 26.
What is the physical state of water at the following temperatures? (a) 25 °C (b) 0 °C (c) 100 °C
Q 27.
Why do diffusion become faster at higher temperatures?
Q 28.
Convert the following temperature to Celsius scale: (a) 300 K (b) 573 K
Q 29.
What are the characteristics of matter?
Q 30.
Why does the temperature of a substance remain constant during melting and boiling even when heat is being supplied to it continuously?
Q 31.
In which case evaporation of water will be faster i.e. near the sea or far away from the sea.
Q 32.
Define the following terms:
a. Melting point
b. Freezing point
c. Boiling point
Q 33.
Why does steam cause more severe burns than boiling water, though both are at the same temperature?
Q 34.
How vapour is different from gases? Give examples of each.
Q 35.
Which of the following state does not exist at room temperature conditions: a) Solids b) Liquids c) Gas d) Plasma
Q 36.
Why do gases diffuse rapidly?
Q 37.
Why is ice at 273 K more effective in cooling than water at the same temperature?
Q 38.
Convert the temperature of 573 K to the Celsius scale.
Q 39.
What factors affect the rate of evaporation?
Q 40.
A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?
Q 41.
What are the conditions for 'something' to be called 'matter' ?
Q 42.
The Kelvin scale temperature is 0 K. What is the corresponding Celsius scale temperature ?
Q 43.
Give reasons to justify: (a) Water at room temperature is a liquid. (b) An iron almirah is solid.
Q 44.
What is the scientific name of particles which make up matter ?
Q 45.
Write the relation between Kelvin scale and Celsius scale of temperature.
Q 46.
What causes evaporation?
OR
Explain evaporation and its cooling effect in terms of kinetic energy of particles.
Q 47.
Is smell of garlic or perfume a matter?
Q 48.
Why do solids expand a bit on heating and contract a bit on cooling?
Q 49.
Name the process by which a drop of ink spreads in a beaker of water.
Q 50.
Write the full forms of the following :(a) LPG (b) CNG
