Holiday HW Class VII

Holiday HW Class VII

Subject	Assignment	Project
English	Diary Entry of your interactions with people over a period of 1 week. Cover it and illustrate it. HW: Write 50 verbs and their forms	Book Review
Hindi	लेखन कार्य : भाषा सम्बन्धी प्रश्न कीजिये | 1.   भाषा की परिभाषा लिखिए | 2.   भाषा के कितने रूप हैं ? 3.   भाषा के रूपों की परिभाषा लिखिए |	परियोजना कार्य : हेलेन केलर का चित्र चिपकाकर उनके संबंध में कुछ पंक्तियाँ    लिखिए |
SST	Pictures with write up on i.                     Chipko Movement ii.                   Narmada Bachao Andolan	History: Poster/Collage (Related to Medieval Period)
Maths	Worksheet on integers	On A4 size paper write the properties of intergers in tabular form w.r.t addition, subtraction, multiplication and division with one example each.
Science	Worksheet on animal fibres	Research Based: Collect information on different types of thermometers, their history along with pictures and write about any one scientist who worked on thermometer.
Sanskrit	लेखन कार्य : एक प्रार्थना लिखिए |	परियोजना कार्य : हिन्दी में रामायण लिखिए |

Answer the following questions

1.  what are the states of Matter around us?
2. . In which state of matter there will be maximum force of attraction between particles?
3.    When heat is being supplied to a solid, then what does the heat energy do to the particles of solid?
4.   Why is it that a wooden chair should be called a solid and not a liquid?
5. Liquid to gas and gas to liquid changes are called:- 
6.  (a) vaporization and condensation (b) condensation and vaporization (c) sublimation and condensation (d) condensation and sublimation
7.  What happens when the temperature of the solids increase? 
8.  When heat is being supplied to a solid, then what does the heat energy do
9. Which of the following is not fluid - a. water, b. air, c. sand, d. sharbat? 
10. Dry ice means – a. solid SO2 b. solid water c. solid CO2 d. solid CO

Assignment classs9
Find out about the applications of chemistry in our daily life.
1. Why solids cannot be compressed like gases?
2.Which of the fo;;owing states do not exist at roon temperature conditions
   Solids, liquids, gases, Plasma
3. why do diffusion becomes faster at higher temperature?
4. Water at room temperature is a liquid. Why?
5. A diver is able to cut through water in a swimming pool. Which property of matter does this  observation show?

CLASS 9 What is the state of inter particle distance in a solid, liquid and gas?              In solids, the particles are very close to each other and are bonded by strong forces of attraction so inter particle distance is least. In liquid, the particles are far away from each other and are bonded by weak forces of attraction, so inter particle distance is large.  In gases, particles are very far apart from each other and are bonded by very weak forces of attraction so, inter particle distance is a largest.

Why it is that to smell cold food, we have to go close but smell of hot food reaches us several meters away?     In hot food, the particles are at high temperature so quickly changes to vapour and hence the vapours have greater kinetic energy so travel faster and travel to far off distances. Whereas in cold food, because of temperature being low, particles do not change to vapour state and hence cannot travel faster so the smell does not reaches to a Person sitting far away.

Why is it that a wooden chair should be called a solid and not a liquid?        A wooden chair should be called a solid not a liquid because the particles of wooden chair are very close to each other, it has negligible compressibility and it maintains its shape when subjective to outside force.

What happens when the temperature of the solids increase ? When temperature of the solid is increased, kinetic energy of the particles increases as results particles vibrates more freely with greater speed. They overcome the force of attraction between the particles and start moving more freely.

When heat is being supplied to a solid, then what does the heat energy do to the particles of solid? The heat supplied to the solid, helps the particles to overcome the forces of attraction between them and increases their kinetic energy, as a result of which particle break free the forces of attraction and changes to liquid state.

 students of class9 refer CBSE notes for Class 9 chemistry on Matter in our Surroundings for notes.click here for lesson notes

Q.1 Define matter.

Ans: Anything that occupies space and has mass and is felt by senses is called matter.

Q.2 what happens if you put copper sulphate crystals in water?

Ans: Copper sulphate crystals mixed between the spaces of molecules of water and disappear.

Q.3 A substance has a definite volume but no definite shape? State whether this substance is a solid, a liquid or a gas.

Ans: Liguid

Q.4 Arrange the following substances in increasing order of force of attraction between the particles. 
(a) Milk (b) Salt (c) Oxygen.

Ans: Oxygen < Milk< Salt

Q.5 A substance has neither a fixed shape nor a fixed volume . State whether it is a solid , a liquid or a gas.

Ans: Gas

Q.6 The melting point of a substance is below the room temperature. Predict its physical state.

Ans: Ice

Q.7 What is vapour ?

Ans: A substance that found in gaseous state only at room temperature is called Vapour

Q.8 Name the temperature at which the solid and liquid states of substance can exist together.

Ans; 0 degree C

Q.9 What is the effect of pressure on boiling point?

Ans: boiling point  increases with  increase in pressure.

Q.10 Name any two substances which sublime.

Ans: Camphor and Naphthalene, iodine and Ammonium chloride iodine

Q.11 Define Condensation.

Ans: The change of solid state from liquid state on cooling is also known as Condensation.

Q.12 For any substance, why does the temperature remain constant during the change of state?

Ans: On increasing the temperature of solids, the kinetic energy of the particles increases which is used to overcome the forces of attraction between the particles therefore the temperature remain constant during the change of state.

Q.13 Which is the slow process , Evaporation or Boiling ?

Ans: Evaporation

Q.14 State the effect of surface area on rate of evaporation.

Ans: If the surface area is increased, the rate of evaporation increases.

Q.15 Why are we able to sip hot tea faster from saucer rather than from a cup?

Ans: This is because the rate of evaporation is faster from saucer.

Q.16 What is the SI unit of temperature?

Ans: Kelvin

Q.17 Kelvin scale of temperature is regarded as better scale than Celsius. Why?

Ans: As it has wide range of measurement and Kelvin scale of temperature has always positive sign , hence regarded as better scale than Celsius.

Q.18.  Convert 10^oC into Kelvin scale.

Ans: 270 + 10 = 280 K

Q.19 Pressure on the surface of a gas is increased. What will happen to the inter particle forces?

Ans: come closer and compressed

Q.20 A gas can exert pressure on the walls of the container. Assign reason.

Ans: As its partials move rapidly due to high kinetic energy.