Viraf J. Dalal solutions for New Simplified Middle School Chemistry [English] Class 6 chapter 4 - Water [Latest edition]

State the sources of water :
on the earth’s surface

State the sources of water :
below the earth’s surface

Give the importance of water in life processes

Give the importance of water in household purpose

Give the importance of water in Fire fighting

Give the importance of water in transportation.

Explain how water plays an important role in the Industry.

Explain how water plays an important role in Agriculture.

Give the occurrence of water in the three different states i.e. solid, liquid, and gaseous.

Draw a labelled diagram to show the change of state of water from solid-state to liquid state to the gaseous state starting from ice.

Explain the term water cycle. State the main points to show how water moves from the earth’s surface to the atmosphere and back to the earth’s surface as rain

Give a reason why water is considered a universal solvent.

Define the term – solute

Define the term – solvent

Define the term:
Solution with reference to the addition of sodium chloride to water

Draw a neat labelled diagram of the addition of copper sulphate to water. Label solute, solvent, and solution in the same.

From the following substances given below state which will form a solution in the same.
(a) sodium carbonate
(b) calcium carbonate
(c) charcoal powder
(d) sodium sulphate
(e) table salt
(f) powdered particles of lead from a lead pencil
(g) iron powder
(h) copper filings
(i) sand particles
(j) honey

Name two gases which are soluble in water

Name two gases which are insoluble in water.

If ‘X’ g. of potassium nitrate is added to 100 g. of water at 60°C and the salt dissolves completely then :

(a) is ‘X’ g. the solubility of potassium nitrate at 60°C.
(b) is the solution formed – saturated or unsaturated
(c) if on addition ‘X’ + ‘Y’ g. of potassium nitrate to the same amount of water at the same temperature and the solute now just remains behind after stirring then –
(d) is the solution now – saturated or unsaturated
(e) is ‘X’ + ‘Y’ g. the solubility of potassium nitrate.

State whether the following statement is true or false. If false write the correct statement.
Solubility of most solids – decreases with increase in temperature

State whether the following statement is true or false. If false write the correct statement.
Distilled water is potable water.

State whether the following statement is true or false. If false write the correct statement.
The process to remove germs in water is also called sterilization

Differentiate between chemical pollution and thermal pollution.

State some important steps to avoid pollution of water.

State what is meant by the term ‘conservation of water’.
State a few water-saving methods, which may be used in the home to conserve water.

Give a reason why :
Conservation of water is essential in spite of the fact that three fourth of the earth’s surface is covered by water.

Give a reason why :
Polluted water causes disease.

Give a reason why :
Drip irrigation helps in the conservation of water.

Complete the statement by filling in the blanks with the correct words.

________ is the purest form of water. It may dissolve gases like ________forming weak acids.

(sea water/ lake water/rain water ; chlorine/ammonia/carbon dioxide)

Complete the statement by filling in the blanks with the correct words.

Water generates ______in hydroelectric power stations and ________in boilers for industrial applications.

(carbon dioxide/steam/heat/electricity)

Complete the statement by filling in the blanks with the correct words.

Water is added to the atmosphere by _____________and _____________.

(burning of fossil fuels/condensation of vapour/ respiration by living organisms/photosynthesis)

Complete the statement by filling in the blanks with the correct words.

If potassium nitrate is added to water in a beaker to give a homogeneous mixture, then potassium nitrate is referred to as the __________, water as the __________, and the homogeneous mixture as the _______.

(solution/ solute/solvent/saturated solution)

Complete the statement by filling in the blank with the correct words.

Water fit for human consumption and drinking purposes is called ____________.

State whether the following statement is true or false. If false, write the correct statement.

Sea water contains salts of calcium and magnesium.

State whether the following statement is true or false. If false, write the correct statement.

Water finds application as a means of transporting goods.

State whether the following statement is true or false. If false, write the correct statement.

On boiling water exists in the liquid state.

State whether the following statement is true or false. If false, write the correct statement.

Respiration uses up water from the atmosphere.

State whether the following statement is true or false. If false, write the correct statement.

Well water exists below the impervious rocky layers of earth.

State whether the following statement is true or false. If false, write the correct statement.

Sodium carbonate and sodium sulphate do not form an aqueous solution.

State whether the following statement is true or false. If false, write the correct statement.

If ‘X’ g. of solute is added to 100 g. of water at t°C and the solution formed is a saturated solution, then ‘X’ g. is the solubility of the solute.

State whether the following statement is true or false. If false, write the correct statement.

Purification of water is carried out to remove – dissolved gases e.g. carbon dioxide and dissolved minerals like magnesium salts.

State whether the following statement is true or false. If false, write the correct statement.

Water from rivers and lakes is – potable water.

State whether the following statement is true or false. If false, write the correct statement.

Chemical pollutants include a metallic salt solution of mercury and lead.

Match the statements in List I, 1-10 with their correct answer in List II, A to J.

Explain the meaning of the following term:

Rainwater harvesting

Explain the meaning of the following term:

Drip irrigation in agriculture

Explain the meaning of the following term:

Saturated solution

Explain the meaning of the following term:

Conservation of water

Explain the meaning of the following term:

The gaseous state of water in the air

Name the following

A chemical used during chlorination of water.

Name the following

An agricultural pollutant in water

Name the following

A solid, ‘natural form of water.

Name the following

The natural process by which circulation of water takes place from the earth’s surface to the atmosphere and back to the earth’s surface.

Name the following

The liquid or medium of dissolution which allows the solute to dissolve in it.