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?

( 1 mark )

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

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

( 1 mark )

(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

( 1 mark )

(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

( 1 mark )

(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

( 1 mark )

(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

( 1 mark )

(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

( 1 mark )

(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

( 1 mark )

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

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

( 1 mark )

(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.

Maths Triangles class 8th   (Q.1)  By which congruency property, the two triangles connected by the following figure are congruent.

( 1 mark )

(a) SSA property
(b) SSS property
(c) AAS property
(d) ASA property

(Q.2)  If a, b and c are the sides of a triangle, then

( 1 mark )

(a) a – b > c
(b) c > a + b
(c) c = a + b
(d) b < c + a

(Q.3)  In the adjoining figure, CD is parallel to AB, then the value ofy will be

( 1 mark )

(a) 30⁰.
(b) 60⁰.
(c) 90⁰.
(d) 120⁰.

(Q.4)  The word CPCT stands for

( 1 mark )

(a) corresponding parts of congruent triangles.
(b) corresponding pair of congruent triangles.
(c) congruent part of corresponding triangles.
(d) congruent pair of corresponding triangles

(Q.5)  Angles opposite to equal sides of an isosceles triangle are

( 1 mark )

(a) complementary.
(b) supplementary.
(c) equal.
(d) not equal

(Q.6)  If the altitudes of a triangle are equal, then the triangle will be

( 1 mark )

(a) a scalene triangle.
(b) an isosceles triangle.
(c) an equilateral triangle.
(d) a right-angled triangle.

(Q.6)  In the given figure, BD and CE are two altitudes of a triangle ABC, such that BD = CE, then the triangle ABC will be

( 1 mark )

(a) a right- angled triangle.
(b) a scalene triangle.
(c) an equilateral triangle.
(d) an isosceles triangle.

(Q.7)  If the measurements of three angles of a triangle are x, 2x and 3x, then the value of x will be

( 1 mark )

(a) 30⁰.
(b) 40⁰.
(c) 50⁰.
(d) 55⁰.

(Q.8)  The value of x as shown in figure,is

( 1 mark )

(a) 70^o.
(b) 82⁰.
(c) 95⁰.
(d) 130⁰.

(Q.9)  In the figure given below, the value of x will be

( 1 mark )

(a) 26⁰.
(b) 50⁰.
(c) 54⁰_.
(d) 100⁰.

(Q.10)  The criterion, by which the given triangles are congruent is

( 1 mark )

(a) SSS.
(b) SAS.
(c) ASA.
(d) AAS.

(Q.11)  The value of x in the following figure is

( 1 mark )

(a) 250⁰.
(b) 125⁰.
(c) 110⁰.
(d) 55⁰.

(Q.12)  The number of sides of a regular polygon whose each exterior anglehas a measure of 1200 are

( 1 mark )

(a) 6.
(b) 5.
(c) 4.
(d) 3.

(Q.13)  The sum of three sides of a triangle is

( 1 mark )

(a) equal to the sum of its three altitudes.
(b) equal to the sum of its median.
(c) less than the sum of its median.
(d) greater than the sum of its median.

(Q.14)  The point of intersection of the perpendicular bisectors of the sides of a triangle is called its

( 1 mark )

(a) orthocentre.
(b) circumcentre.
(c) centroid.
(d) incentre.

(Q.15)  The point of intersection of all the three medians of a triangle is called its

( 1 mark )

(a) orthocentre.
(b) circumcentre.
(c) centroid.
(d) incentre.

(Q.16)  The point of intersection of the internal bisectors of the angles of a triangle is called its

( 1 mark )

(a) orthocentre.
(b) circumcentre.
(c) centroid.
(d) incentre.

(Q.17)  The value of x in the given figure is

( 1 mark )

(a) 150⁰.
(b) 130⁰.
(c) 100⁰.
(d) 85⁰.