CHEMISTRY | Raman

Class 6

Fill in the Blanks

edit ________________ (Rainwater/Surface water) is the purest form of water. Answer : Rainwater
edit The density of water is maximum at ________________. Answer : 4°C
edit ________________ is the amount of heat energy required to raise the temperature of a liquid by 1°C. Answer : Specific heat capacity
edit Large amount of water is also given out by the leaves of plants during ________________. Answer : transpiration
edit Water helps in the excretion of waste from the body in the form of ________________, urine or while breathing. Answer : sweat
edit Water is very important for ________________ of seeds. Answer : germination
edit About ________________ of the fresh water is present in rivers, lakes, springs, ponds, etc. Answer : one-third
edit In ________________ state, water exists as snow or frost. Answer : solid
edit Water exists as ________________ or ________________ in gaseous state. Answer : water vapour, steam
edit The density of water is ________________ at 4 degree Celsius. Answer : maximum
edit Water regulates the body ________________ of plants and animals. Answer : temperature
edit Water acts as a ________________ in powerhouses which generate electricity. Answer : coolant
edit Solubility of a solute ________________ on increasing the temperature. Answer : increases
edit A solution is said to be ________________ when it can dissolve more of the solute at a particular temperature. Answer : unsaturated
edit ________________ is an infection in the small intestine caused by a bacterium. Answer : Cholera
edit The addition of unwanted and harmful substances to water is called ________________. Answer : water pollution

Fill in the blanks with anxwers

(a) Water is a universal; solvent.

(b) Rainwater is the purest form of natural water.

(c) Sand and dust are suspended impurities in water.

(d) Sea water has high concentration of salt (impurity).

(e) Water covers nearly 4 / 5 th of the surface of the earth.

(f) Evaporation of rain water leaves NO residue.

(g) Potash alum is the chemical added to water to remove the tiny suspended particles.

(h) A solution is a uniform mixture of a solute and a solvent.

(i) Ice, water and steam have different physical states but are chemically identical.

(j) Boiling kills most of the germs in water.

(k) The elements present in the molecules of water are hydrogen and oxygen.

1. Water is essential for running .......................... power plants.1

2. A sample of water which is fit for human .......................... is called potable water.

3. A solution which cannot dissolve more of solute is called ............................. solution.

4. Distilled water is ...................................... water.

5. Fish die in ................................. ponds during summer season

Answers

Fill in the blanks

1. hydroelectric

2. consumption

3. saturated

4. pure

5. shallow

Class 8

1. Fill in the blanks:

(a) Water has maximum density and minimum volume at 4°C.

(b) Freezing mixture contains ice and salt.

(d) Rain water is the purest form of natural water.

(e) Use of excessive fertilizers by farmers causes water pollution.

(f) Boiling removes the temporary hardness of water.

(g) Water turns the colour of anhydrous copper sulphate blue.

(h) Water turns the colour of anhydrous copper sulphate scum.

Class 9

Fill in the blanks:

Water forms about ________ of human body and almost ________ of some plants.
________ is used for drinking purpose.
A solution of iodine in alcohol known as ________.
Anhydrous substance lack their ________.
Concentrated ________ remove water of molecules from blue vitriol. It is a ________ agent.
Washing soda contains ________ molecules of water of crystallisation.
The higher the temperature of the air, the ________ the efflorescence.
Land and sea breeze are caused by ________ property of water. [specific heat capacity/latent heat of vaporisation]
________ gas is more soluble in water. [nitrogen/oxygen]
Air is the example of ________ solution.
The boiling point of water ________ due to the presence of dissolved impurities. [increases/decreases]
Water molecule has _______ bonding in it. [ionic, covalent]

(i) 65%, 95% (ii) Soft water (iii) tincture of iodine (iv) water of crystalisation (v) sulphuric acid, dehydrating (vi) ten (vii) higher (viii) specific heat capacity (ix) oxygen (x) gaseous (xi) increases (xii) covalent

A.L. Lavoisier, in the year (i) ________ showed that water is a compound of (ii) ________ and (iii) ________ atoms combined together in the ratio of (iv) ________.

Answers ;

(i) 1781, (ii) hydrogen, (iii) oxygen, (iv) 2 : 1

Water MCQ

Water notes

Short Notes

Water Fill in the Blanks