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 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 are the ways a gas can be liquefied?
Q 6.
What is evaporation? Why does evaporation cause cooling?
Q 7.
Which state of matter is most easily compressible?
Q 8.
List any five physical properties of liquids.
Q 9.
What do you mean by the term Volume?
Q 10.
Define the term Volatile Liquid.
Q 11.
Why solids cannot be compressed like gases?
Q 12.
Define transpiration.
Q 13.
Arrange the following substances in increasing order of intermolecular force of attraction: water, sugar, oxygen
Q 14.
What are the differences between boiling and evaporation?
Q 16.
What do you mean by the following terms:
a. Evaporation
b. Sublimation
c. Condensation
Q 17.
Define evaporation.
Q 18.
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 19.
Define Latent Heat of Fusion and Latent Heat of vaporisation.
Q 20.
Why is light not considered matter?
Q 21.
Our own bodies contain examples of all three states of matter. Can you identify these?
Q 22.
How matter is classified in terms of composition?
Q 23.
How can matter change its state?
Q 24.
How vapour is different from gases? Give examples of each.
Q 25.
Which of the following state does not exist at room temperature conditions: a) Solids b) Liquids c) Gas d) Plasma
Q 26.
What is the physical state of water at the following temperatures? (a) 25 °C (b) 0 °C (c) 100 °C
Q 27.
In which case evaporation of water will be faster i.e. near the sea or far away from the sea.
Q 28.
Why do diffusion become faster at higher temperatures?
Q 29.
Why do gases diffuse rapidly?
Q 30.
Which of the following are matter?
Chair, Air, Love, Smell, Hate, Almonds, Thought, Cold, Cold drinks, Smell of perfume
Q 31.
Convert the following temperature to Celsius scale: (a) 300 K (b) 573 K
Q 32.
Why does the temperature of a substance remain constant during melting and boiling even when heat is being supplied to it continuously?
Q 33.
Convert the temperature of 373°C to the Kelvin scale.
Q 34.
Name the process by which a drop of ink spreads in a beaker of water.
Q 35.
What is the (a) common unit of temperature, and (b) SI unit of temperature ?
Q 36.
What factors affect the rate of evaporation?
Q 37.
What is meant by saying that the latent heat of vaporisation of water is 22.5 x
Q 38.
What is the general name of : (a) rigid form of matter ? (b) fluid forms of matter ?
Q 39.
Honey is more viscous than water. Can you suggest why ?
Q 40.
What are the conditions for 'something' to be called 'matter' ?
Q 41.
State whether the following statement is true or false : Solid carbon dioxide is stored under low pressure.
Q 42.
Write the full forms of the following :(a) LPG (b) CNG
Q 43.
What are the characteristics of matter?
Q 44.
Explain with an experiment to show gases do not have fixed shape or volume.
Q 45.
Differences among solids, liquids and gases.
Q 46.
What is the scientific name of particles which make up matter ?
Q 47.
Convert the temperature of 573 K to the Celsius scale.
Q 48.
The Kelvin scale temperature is 0 K. What is the corresponding Celsius scale temperature ?
Q 49.
Give the usual name for the following :Heat required to change the state of a substance without changing the temperature.
Q 50.
(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.
