Chemistry Standard 8 Assignment

 

St. MARY’S C G H S S ERNAKULAM

Std 8 Chemistry test paper chapter 1 & 2

1.Solids that easily change into gases without changing into liquids are called ................... substances

a. superfluid

b. volatile

c.sublimable

2.Change of gas into liquid is called .............................

a. liquifaction

b. sublimation

c. condensation

3.Spontaneous mixing of different particles having freedom of movement is called ...................

a. distillation

b.diffusion

c. evaporation

4. More than one solute dissolved in the same solvent can be separated by ..........................

a. chromatography

b. centrifugation

5.Insoluble particles in a liquid mixture can be separated on the basis of their mass difference using the method ..........................................

a. separating funnel

b. centrifugation

6. When liquid changesinto gas force of attraction between molecules ..............................

a. increases

b. decreases

c. does not change

7.Which is the method of separating a mixture of miscible liquids when there is a large difference between the boiling points of the liquids

a. evaporation

b. distillation

c. fractional distillation

8.Pure substances which cannot be decomposed through chemical processes are called ........................

a. elements

b. compounds

9.Match the following elements and their symbols

Calcium Fe

Carbon Cu

Helium Br

Chlorine Be

Potassium K

Bromine Cl

Berilium He

Sulphur C

Copper S

Iron Ca

10. Which of the following is a polyatomic molecule?

a. sodium

b. phosphorous

c. bromine

11.Which of the following are elements ?

a. Iron

b. water

c. Nitrogen

d.Ammonia

12. How many atoms are present in 7H₂

a. 7

b. 2

c. 14

13. How many molecules are present in 3H₂O

a. 3

b. 6

c.9

14.CaCO₃ ---> CaO + CO_2. Is it a balanced equation ?

a. yes

b. no

15. C + O₂ ---> CO₂ What is the product in this reaction ?

a. Carbon

b. Oxygen

c. Carbon dioxide