Is Matter Around Us Pure

Question 1

What is a pure substance?

Answer 1

A substance which consists of only a single type of constituent particle is called a pure substance.

Question 2

What is an element?

Answer 2

An element is a basic form of matter that cannot be broken down into simpler substances by chemical reactions.

Question 3

What is a mixture?

Answer 3

A mixture is substance which consist of two or more elements or compounds not chemically combined together.

Question 4

What are the two types of mixtures?

Answer 4

Homogeneous mixtures and heterogeneous mixtures

Question 5

What is a homogeneous mixture?

Answer 5

A mixture in which the constituents are distributed throughout without any clear boundary of separation.

Question 6

What is a heterogeneous mixture?

Answer 6

A mixture that does not have uniform composition and it has a visible boundary of separation between its constituents.

Question 7

What are the properties of mixtures?

Answer 7

1) A mixture can be separated into its constituents by physical processes
2) A mixture shows all the properties of its constituents present in it
3) Energy is neither given out nor absorbed during the preparation of mixtures
4) The composition of mixtures is variable
5) Mixtures does not have fixed melting and boiling points

Question 8

What are the differences between homogeneous and heterogeneous mixtures?

Answer 8

Homogeneous
1) The constituents are uniformly distributed throughout
2) There is no visible boundary of separation between the constituent
3) The constituent cannot be separated easily, special methods are required for this purpose
Heterogeneous
1) The constituents are not distributed uniformly
2) There are visible boundary of separation
3) Constituents can be easily separated by simple methods

Question 9

What is a compound?

Answer 9

It is a substance made up of two or more elements combined together in a fixed proportion by mass.

Question 10

What are the properties of compounds?

Answer 10

1) A compound not be separated into its constituents by physical processes
2) Properties of compounds are entirely different from that of its constituents
3) Energy is either given out or absorbed during the preparation of compounds
4) The composition of compounds is fixed
5) Compounds have fixed melting and boiling point.

Question 11

What is a solution?

Answer 11

It’s a homogeneous mixture of two or more substances.

Question 12

What is tincture iodine?

Answer 12

A solution of iodine in alcohol

Question 13

What is solvent?

Answer 13

The component of solution that dissolves the other component in it.

Question 14

What is solute?

Answer 14

The component of the solution that is dissolved in the solvent.

Question 15

What are the properties of solutions?

Answer 15

1) Solution is a homogeneous mixture.
2) The particles of solution are smaller than 1 nanometer in diameter
3) The solution do not scatter the beam of light, so the path of the light is not visible.
4) The solutions are stable, that is the solute particles do not settle down when left undisturbed.
5) The solutions cannot be seperated by the process of filteration.

Question 16

Define the concentration of a solution.

Answer 16

It is the amount of solute present in a given amount of solution.

Concentration of solution =
Mass of solute/Mass of solution ×100

Question 17

Formula to find the mass of solution

Answer 17

Mass of solution = Mass of solvent + mass of solute

Question 18

What is suspension?

Answer 18

It is a heterogeneous mixture in which the solute particles do not dissolve but remain suspended throughout the bulk of the medium.

Question 19

What are the properties of suspension?

Answer 19

1)Suspension is a heterogeneous mixture.
2) The particles of suspension are greater than 100 nanometer in diameter
3) The suspension scatters the beam of light, so the path of the light is visible.
4) The suspension is unstable, that is the solute particles settle down when left undisturbed.
5) The suspension can be seperated by the process of filteration.

Question 20

What are colloids?

Answer 20

It is a mixture that is actually heterogeneous but appears to be homogeneous as the particles are uniformly spread throughout the solution

Question 21

What are the properties of colloids?

Answer 21

1) Colloids is a heterogeneous mixture.
2) The particles of colloids are greater than solution and smaller than suspension
3) The colloids scatters the beam of light, so the path of the light is visible.
4) The colloids are stable, that is the solute particles do not settle down when left undisturbed.
5) The colloids can not be seperated by the process of filteration.

Question 22

What are the differences between physical change and chemical change?

Answer 22

Physical change
1) no new substances formed in a physical change
2) it is a temporary change
3) it is easily reversible
4) the mass of a substance does not alter in physical change
Chemical change
1) new substances formed in a chemical change
2) it is a permanent change
3) it is not easily reversible
4) the mass of a substance does alter in chemical change

Question 23

What are the differences between physical change and chemical change?

Answer 23

Physical change
1) no new substances formed in a physical change
2) it is a temporary change
3) it is easily reversible
4) the mass of a substance does not alter in physical change
Chemical change
1) new substances formed in a chemical change
2) it is a permanent change
3) it is not easily reversible
4) the mass of a substance does alter in chemical change