Selina solutions concise chemistry class 9 icse Solutions for Chapter 3 chapter 3 water

Water exists in all three states. Discuss

Why water is considered a compound.

a) Why does temperature in Mumbai and Chennai not fall as low as it does in Delhi?

b) Give the properties of water responsible for controlling the temperature of our body.

Water is a universal solvent’ comment

What causes the violence associated with torrential rain?

The properties of water are different from the properties of the elements of which it is formed. Discuss.

What are your observations and conclusion when tap water is boiled and evaporated in the watch glass

How is air dissolved in water different from ordinary air?

Explain why the hot saturated solution of potassium nitrate forms crystals as it cools

a) If you are given some copper sulphate crystals, how would you proceed to prepare its saturated solution at room temperature?

b) How can you show that your solution is really saturated?

Give the names and formulae of two substances in each case

a) Hydrated substance b) anhydrous substance

c) liquid drying agent d) a basic drying agent

What is the effect of temperature on solubility of KNO3 and CaSO4 in the water’?

The solubility of NaCl at is 400 c is 36.5 g. What is meant by this statement

Which test will you carry out to find out if a given solution is saturated or unsaturated or

supersaturated?

What is the effect of pressure on the solubility of gases? Explain with an example

State the term : (Do not give examples)

(a) A solution where the solvent is a liquid other than water.

(b) When a substance absorbs moisture on exposure to moist air and dissolves in the absorbed water and turned to a solution.

(c) A substance that contains water of crystallization.

(d) When a substance absorbs moisture from the atmosphere but does not form a solution.

(e) When a compound loses its water of crystallization on exposure to dry air.

(f) The substance that can remove hydrogen and oxygen atoms in the ratio of 2: 1 (in the form of water from the compounds.

Explain why :

a) water is an excellent liquid to use in cooling systems.

b) a solution is always clear and transparent.

(c) lakes and rivers do not suddenly freeze in the winters.

(d) the solute cannot be separated from a solution by filtration.

(e) Fused CaCl2 or conc. H2SO4 is used in a desiccator.

(f) effervescence is seen on opening a bottle of soda water.

(g) Table salt becomes sticky on exposure to humid air during the rainy season

What is the composition of water ? In what volume its elements combine ?

A hot saturated solution of sodium nitrate forms crystals, as it cools. Why

Name the three methods by which hydrous substances can be made anhydrous.

What do you understand by

(a) Soft water

(b) Hard water

(c) Temporary Hard water

(d) Permanent hard water

What are the causes of

(a) Temporary hardness

(b) Permanent hardness

10. What are the advantages of

(i) soft water

(ii) Hard water

What are stalagmites and stalactites`’ How are they formed?

Give equations to show what happens when temporary hard water is

(a) boiled

(b) treated with slaked lime

What is the advantage of detergent over soap?

Explain with the equation. what is noticed when permanent hard water is treated with

(a) slaked lime

(b)

washing soda

What is permutit method, how can it be used for softening hard water?