Chapter 2 Matter in our Surroundings

NIOS Class 10 Science and Technology Chapter 2 Textbook Solutions

INTEXT QUESTIONS 2.1

1. What is matter?

Ans: Matter is anything that has mass and occupies space

2. Which of the following is not a pure substance?

(a) Iron (b) Water (c) Soil

Ans: Soil

3. Who coined the term “atom” and what does it mean?

Ans: Democritus. The word atom means indivisible.

INTEXT QUESTIONS 2.2

1. Which of the three states of matter has no definite volume? Give one reason for your answer.

(a) Solid, (b) liquid, (c) gas

Ans: Gases. A gas has no definite volume because intermolecular forces in a gas are so weak that the molecules are far apart and in constant motion. They can fill a container of any size.

2. Why do solids have definite shape?

Ans: The molecules in solids have fixed positions, and strong intermolecular forces act between them. Therefore, it has a definite shape.

3. Name a substance which exists naturally in all the three states.

Ans: Water

INTEXT QUESTIONS 2.3

1. Why are gases more compressible as compared to solids?

Ans: Molecules in solids are closely packed, and any attempt to bring them closer results in strong repulsive forces and so solids cannot be compressed. In gases, there are large spaces between their molecules that can be brought closer by applying pressure.

2. How can you change water into ice?

Ans: Water can be converted into ice by lowering the temperature.

INTEXT QUESTIONS 2.4

1. Classify the following into element, compound and mixture: aluminium, carbon, granite, water, silicon, carbon dioxide, air and sugar.

Ans:

Element	Compound	Mixture
Aluminium CarbonSilicon	Water Carbon dioxideSugar	AirGranite

2. How does an element differ from a compound?

Ans: An element consists of one type of atom, but a compound contains two or more types of atoms.

3. Which is the most abundant element in the universe?

Ans: Hydrogen

INTEXT QUESTIONS 2.5

1. Say whether ethyl alcohol and water form a homogeneous mixture or heterogeneous mixture.

Ans: The mixture of ethyl alcohol and water is homogeneous.

2. Give an example of homogeneous mixture obtained by mixing two solids.

Ans: Alloys, eg, brass

INTEXT QUESTIONS 2.6

1. To make one kilogram of a 40% sugar solution by mass, how much sugar and water will you need?

Sugar

Water

Ans: 400 g sugar and 600 g water

2. What is the name given to a liquid which dissolves a solid to make a solution?

Ans: Solvent

3. To make a given solution more concentrated, what will you add?

Ans: Solute

INTEXT QUESTIONS 2.7

1. Which physical property is used to separate iron granules from dust particles?

(a) Magnetic, (b) Electric, (c) Density

Ans: Magnetic

2. The separation of sugar in the form of Mishree is called

(a) evaporation (b) crystallisation (c) distillation

Ans: Crystallisation

TERMINAL EXERCISE

1. Indicate whether each of the following statements is true or false.

(i) A liquid has a definite shape: true/false

(ii) An element cannot be broken into simpler substances by chemical means. true/false

(iii) A solid cannot be converted into liquid even by increasing temperature. true/false

(iv) A liquid can be converted into solid by lowering temperature true/false

Ans:

(i) False

(ii) True

(iii) False

(iv) True

2. Indicate the normal state (i.e. state at room temperature) of each of the following?

(i) iron

(ii) water

(iii) nitrogen

(iv) carbon

(v) gold

(vi) oxygen

Ans:

(i) iron: Solid
(ii) water: Liquid
(iii) nitrogen: Gas
(iv) carbon: Gas
(v) gold: Solid
(vi) oxygen: Gas

3. In the table given below, a list of substances has been provided. Identify whether each of them is an element, compound, mixture, or solution.

(i) Milk (ii) Sugar (iii) Silver (iv) Air (v) Water (vi) Sea water

(vii) Iron (viii) Sugar (ix) Carbon dioxide

Ans:

(i) Milk: Solution
(ii) Sugar: Compound
(iii) Silver: Element
(iv) Air: Mixture
(v) Water: Compound
(vi) Sea water: Mixture or solution
(vii) Iron: Element
(viii) Sugar: Compound
(ix) Carbon dioxide: Compound

4. Why is it important to store cooking gas cylinder away from heat and flame?

Ans: Temperature affects the volume of the gases. When the temperature increases, volume of the gas also increases. When a closed container or a gas cylinder is heated, it blasts due to a rapid increase in volume.

5. Identify the most appropriate method to separate the following:

1. Separate water from yogurt

2. Separate clean water from muddy water

3. Separate oil from oil water mixture

4. Separate iron nails from sawdust

5. Separate sugar from saturated sugar solution

Ans: