Wednesday, March 6, 2013

Ch.1- Matter in our surroundings 9th Solved Question

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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 10oC 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.

1 comment:

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