Matters in our surrounding

1. Tabulate the differences in the characteristics of states of matter.

2. What are the characteristics of particles of matter?

3. Why a gas fills completely the vessel in which it is kept?

4. Why a gas exerts pressure on the walls of container?

5. Why a wooden table should be called a solid?

6. Why We can easily move our hand in air but to do the same through wooden block, we need karate expert.

7. Arrange the following in order of increasing density – air, exhaust from chimneys, honey, water, chalk, cotton and iron.

8. Liquids generally have lower density as compared to solids. But you must have observed that ice floats on water. Find out why?

9. Comment upon the following : rigidity, compressibility, fluidity, filling a gas container, shape, kinetic energy and density.

10. Which of the following are matter? - Chair, air, love, hate, almonds, thought, cold, lemon water, smell of perfume.

11. Why the smell of hot sizzling food reaches you several meters away, but to get the smell from cold food, you have to go close?

12. A diver is able to cut through water in a swimming pool. Which property of the matter does this observation show?

1. Convert the following temperature to celsius scale : a) 300K b) 573K

2. What is the physical state of water at : a) 2500C b) 1000C ?

3.  For any substance, why does the temperature remain constant during the change of state?

4. Suggest a method to liquefy atmospheric gases.

5. Why does a desert cooler cool better on a hot dry day?

6. How does the water kept in an earthen pot become cool during summer?

7. Why does our palm feel cold when we put some acetone or petrol or perfume on it?

8. Why are we able to sip hot tea or milk faster from a saucer rather than a cup?

9. What type of clothes should we wear in summer?

1. Convert the following temperatures to the celsius scale (a) 293 K(b) 470 K

2. Convert the following temperatures to the kelvin scale. (a) 250C (b) 3730C

3. Why naphthalene balls disappear with time without leaving any solid?

4. Why we can get the smell of perfume sitting several meters away?

5. Arrange the following substances in increasing order of forces of attraction between the particles- water, sugar, oxygen.

6. What is the physical state of water at - (a) 250 C (b) 00C (c) 1000C ?

7. Why is water at room temperature a liquid?

8. Give reason to justify - an iron almirah is a solid at room temperature.

9. Why is ice at 273 K more effective in cooling than water at the same temperature?

9. What produces more severe burns, boiling water or steam?

10. Name A,B,C,D,E and F in the following diagram showing change in its state.

1. People sprinkle water on the roof or open courtyard in summers. Give reason for the same.

2. Surgeons spray some ether on skin before performing minor surgery. Why?

Q.3: Matter is not continuous but made up of small tiny particles. Explain.

Q.4: Do we sweat more on a dry day or on a humid day? Explain.

Q.5: Why wet clothes do not dry easily on a rainy day?

Q.6: After rains, wet roads dry quickly. Give reason.

Q.7: Butter is generally wrapped in wet cloth during summer if no refrigerator is available. Explain.

Q.8: How do wind speed and surface area affect the rate of evaporation?

Q.9:- Write down an activity to show that air contains water vapours.

Q.10:- Why doctors advise to put strips of wet cloth on the forehead of a person having high fever?

Q.11: Water kept in pitchers does not become colder in rainy season than in summer. Explain why?

Q.12: Clothes dry fast in summer than in winters. Why?

Q.13: Define melting point.

Q.14: Define boiling point.

Q.15: Define sublimation.

Q.16: Define evaporation.

Q.17: What is dry ice? What are the various uses of dry ice?

Q.18:- What will be the state of water at (i) 1080C i) 275 K iii) 370 K ?

Q.19: Sugar when kept in Jar of different shapes adopts the shape of the jar, yet we call it solid.

Q.20: How is heating of sugar different from heating of ammonium chloride?

Q.21: If we drop a crystal of copper sulphate in two beakers A and B containing cold and hot water respectively. In which beaker dissolution will be faster and why?

Q.22: A drop of ink and honey are added to water contained in different beakers. Which of the two will spread faster and why?

Q.23:- Ramesh got an invitation to attend a party. On coming to home, he found that both shirt and pants were wet. What steps he would take to dry them quickly?

Q.24: Sponge is a solid, yet we are able to compress it. Give reasons.