chemisty matter in our surrounding

       Chemisty - class 9th

 Matter and its compositions, Mixtures

(Q.1)  On heating, kinetic energy of the molecules:

( 1 mark )

(a) Decreases
(b) Increases
(c) Either decreases or increases
(d) Remains same

(Q.2)  Which of the following does not affect evaporation?

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(a) Surface area
(b) Humidity
(c) Pressure
(d) Temperature

(Q.3)  The standard room temperature is taken as

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(a) 0 K.
(b) 273K.
(c) 298K.
(d) 373K.

(Q.4)  Solid carbon dioxide (dry ice) when kept in air, forms carbon dioxide gas by the process of

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(a) sublimation.
(b) diffusion.
(c) fusion.
(d) condensation.

(Q.5)  In the mixture of sand, common salt, ammonium chloride and iron powder, the substance that sublimes is

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(a) sand.
(b) common salt .
(c) ammonium chloride .
(d) iron powder

(Q.6)  When a bottle of perfume is opened in a room, we can smell it even from a considerable distance due to

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(a) osmosis.
(b) diffusion.
(c) fusion.
(d) condensation.

(Q.7)  If ice and water both have the same temperature of 00C, the kinetic energy of water molecules is

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(a) high in both water and ice.
(b) low in both waterand ice.
(c) lower in waterthanice.
(d) higher in waterthan ice

(Q.8)  The right procedure to separate sand, common salt and ammonium chloride from a mixture is

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(a) dissolving in water, evaporating and sublimation .
(b) evaporation, dissolving in water and then, sublimation.
(c) sublimation, dissolving in water, filtration and evaporation.
(d) dissolving in water, filtration, evaporation and sublimation

(Q.9)  Iodine, ammonium chloride and dry CO2 are good examples to show the phenomenon of

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(a) diffusion.
(b) sublimation.
(c) condensation.
(d) evaporation.

(Q.10)  On increasing the temperature, the rate of diffusion of gases

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(a) increases.
(b) decreases.
(c) remains the same.
(d) first decreases then increases.

(Q.11)  What are the factors, that determine the state of a substance? 

(Q.12)  Liquids generally have lower density as compared to solids. But ice floats on water. Why?

(Q.13)  Why do solids generally lack the property of diffusion?

(Q.14)  How will you demonstrate that air contains water vapours?

(Q.15)  Convert the following temperatures into the Kelvin scale.
(a) 25⁰c
(b) 373⁰c

Q.16)  Why are we able to sip hot tea or milk faster from a saucer rather than a cup?

Q.17)  Convert the following temperature to Celsius scale:
(a) 300 k
(b) 573 k.

(Q.18)  Differentiate between evaporation & boiling

Q.19)  Give two reasons to justify.

a) Water at room temperature is a liquid.
b) An iron almirah is a solid at room temperature.

(Q.20)  What are the characteristics of the particles of matter?

(Q.21)  Define the following terms.
Fusion, latent heat of fusion, boiling point, latent heat of vaporization, sublimation.