Question

1. Both the process of evaporation and boiling involves the change of state from liquid to gas but still
they are different from each other. Justify.
2. Why is Kelvin considered as the best scale for measuring the temperature?
3. Camphor disappears without leaving any residue. Explain?
4. What happens when you pour some acetone on your palm?

5. How is heating of sugar and heating of ammonium chloride different from each other? Explain your answer.
6. List three characteristics of particles of matter. Describe one example for each characteristic to illustrate it. Name the characteristics which are responsible for

(i) spreading of smell of scent in a room and (ii) water taking shape of the vessel in which poured.

7. A gas jar containing air in inverted over another containing NO2 gas which is brown in color and heavier than air. After some time brown color is seen in the inverted gas jar too. Identify the phenomena associated with this observation.

8. A spoonful of sugar is added to a beaker containing 500ml of water and stirred for a while.State any two observations that you will make.Account for your observations.
9. (i) List four factors which affect evaporation.
(ii)Describe the activity to show that water is present in the air.
10. Distinguish between solids liquids and gases in tabular form under following headings:
(i)Rigidity (ii) Compressibility (iii) Inter particle force of attraction (iv) Inter particle spaces
11. At what temperature does solid ice and liquid water co-exist together?
12. What is the effect of the following on the rate of diffusion:
a. temperature b. density of liquid
13. a. Define matter. Name the state of matter in which the forces between the constituent particles are
(i)Strongest (ii) Weakest
14. Which characteristic of gas is used in supplying oxygen cylinders to hospital?
15.With the help of a labelled diagram describe an activity to show that nature of matter is particulate and not continuous. Use the following material: beaker, spoon, glass rod, sugar.
16. Give reason :
(a) Steam produces more severe burns as compared to boiling water.
(b) Temperature of a liquid does not change when it boils
(c) A liquid generally flows easily.
(d) Ice at 0◦C appears colder to the mouth than water at 0◦C. Why?
(e) A sponge is a solid but can be easily compressed.
(f)Salt and sugar when kept in different jars take the shape of the jars, yet they are classified as solids.
(g) Doctors advise to put strips of wet cloth on the forehead of a person having high temperature.
(h)The water kept in a pitcher does not become colder in rainy season than in summer.
(i) Water droplets appear on the outer surface of a tumbler containing ice cold water.

(j) People prefer to wear cotton clothes in summer.


(k) On a hot sunny day people sprinkle water on the roof or open ground.
17. Study the given schematic diagram and identify (a) and (b).

18. Arrange the three states of matter in increasing order of their compressibility.

19. Study the given schematic diagram Identify the names of the processes from a to f .Predict which one of the change of states represented by labels (a) to (f) are not possible for water.






20. Ice and water are essentially the same substance. Mention any two differences in their properties.
(a) What is the physical state of the substance at the points A, B, C and D?

(b) What is the melting point of the substance?

(c) What is its boiling point?

(d) Which portions of the graph indicate that change of state is taking place?

(e) Name the terms used for heat absorbed during change of states involved in above processes.


21. The temperature-time graph given below shows the heating curve for pure wax. From the graph answer the following.

Answer 1

Answer:

1. boiling occurs at a fixed temperature but evaporation can take place at any temperature below its boiling point

2. kelvin is universally acknowledged to give same value at any place on earth ,for a constant temperature, so it is taken as si unit of temperature.

3. camphor perform sublimation ,in which at normal temperature and pressure substance converts from solid to gas and vice versa.