Chapter 1

STATES OF MATTER

REVISION PPT

1

1.1 States of Matter

TB Pg 3-6

2

+WHAT IS MATTER?

Matter is something that occupies space

and has mass.

+MATTER

4

Whichever chemical substance we study, we

find that the substance can exist in three

different forms (physical states) depending

on the conditions.

States of Matter

THE THREE STATES OF MATTER

SOLID

LIQUID

GAS

5

+States of matter

Solid Liquid Gas

Has a fixed shape No fixed shape

Takes the shape of the

container

No fixed shape

Has fixed volume Has fixed volume No fixed volume

Takes the volume of the

container

Incompressible Can be compressed a bit Easily compressible

Does not flow Generally flows easily Flows easily

High Density Moderate to high density Low density

+Changes in State

Melting/Freezing

Boiling(vaporization)/Condensing

Sublimation

Evaporation

7

+Conversion from one state to another

+Melting and Freezing Point

The temperature at which a substance turns to a liquid is

called the melting point.

The temperature at which a liquid gets converted back to a

solid is called freezing point.

9

+Evaporation

If a liquid is left with its surface exposed to air, it evaporates.

When liquid changes into gas in this way, the process is

called evaporation.

It occurs from the surface of the liquid.

The larger the surface are, the faster the liquid evaporates.

10

+Boiling

At a certain temperature a liquid becomes hot enough for

gas to form within the liquid and not just at the surface.

This process is known as boiling.

The temperature at which a liquid changes to gas is called its

boiling point.

11

+Volatile and Volatility.

Volatile substance are those substances which evaporates

easily.

It’s a liquid with a low boiling point.

Volatility is the property of how easily a liquid evaporates.

12

+

1.1 STATES OF MATTER

TB Pg 7-10

+PURE SUBSTANCE

A pure substance consists of

only one substance without

any contaminating impurities.

A pure substance melts and

boils at definite temperatures.

+

CRITERIA FOR PURITY

The purity of a substance can be measured by :-

1. Its melting point:- Pure substances have a sharp melting point.

If impurities are present then melting occurs over a wide range

of temperature.

2. Its boiling point:-Pure substances have a sharp boiling point. If

impurities are present then boiling occurs over a wide range of

temperature.

+STATE OF A SUBSTANCE

A substance’s melting and boiling points in relation

to the temperature (standard taken as 250C)

determine whether it is usually seen as a solid,

liquid or gas.

For example, if the melting point is below 250C and

the boiling point is above 250C, the substance will

be a liquid at room temperature.

+EFFECT OF IMPURITIES

Impurities often affect the value of melting and

boiling point of a substance.

An impure substance sometimes melts or boils over

a range of temperatures, not at the precise point of

the pure substance.

When impurities are present the freezing point

decreases and the melting point increases.

+

120

90

60

30

0

2 4 6 8 100

Te

mp

era

ture

(°

C)

Time (s)

-30

Heating and cooling curves

Boiling

Point

Melting

Point

+What happens on heating

Matter is made up on small particles which are in constant

motion.

When you heat matter, the particles of matter absorb the heat

energy and begin moving faster (in other words they gain

kinetic energy).

As more energy is provided the chemical bond between the

particles become weaker and hence there is change is the state

of matter.

+

1.2 KINETIC THEORY OF MATTER

TB Pg 11-14

+1.2 Kinetic Theory of Matter

Kinetic Theory of matter

explains the relation between

matter and energy of the

particles present in matter.

21

+ 22

Main points of Kinetic Theory of

Matter

1) All matter is made up of very small particles

called atoms. Different substances contain

different types of particles such as atoms,

molecules or ions.

+Main points of Kinetic Theory of

Matter2) These tiny particles are always in

motion.

Increase in temperature = increase motion of

particles

decrease in temperature = decrease in

motion of particles

23

+Main points of Kinetic Theory of

Matter

3) The freedom of movement and

arrangement of particles is different for the

three states of matter.

24

+Main points of Kinetic Theory of

Matter

4) The pressure of the gas is produced by the

atoms or molecules of the gas hitting the

walls of the container. The more often the

particles collide with the walls, the greater

the pressure.

25

+STATES OF MATTER AND KINETIC

THEORY

+

1.3 MIXTURES OF SUBSTANCES AND DIFFUSION

TB Pg 14-18

+What is a mixture?

When two or more materials

or substances are mixed

together but do not chemically

combine.

This means they retain their

original properties.

This means they can be

separated by physical means.

+TYPES OF MIXTURES

HOMOGENEOUS

MIXTURESHETEROGENEOUS

MIXTURES

The prefixes "homo"-

indicate sameness

The prefixes: "hetero"-

indicate difference.

A homogeneous mixture has

the same uniform

appearance and

composition throughout.

A heterogeneous mixture

consists of visibly different

substances or phases.

+Solutions

When the states are completely mixed to become

one single state or phase the mixture is called a

solution.

+Solutions

The solid that dissolves in a liquid is called solute.

The liquid in which the solid dissolves is called the

solvent.

+SOLUTIONS

If a substance dissolves in a solvent it

is said to be soluble and if does not

dissolve it is said to be insoluble.

When two liquids mix with each other

they are said to be miscible and if

they don’t mix they are said to be

immiscible.

Alloys are mixtures of metals.

+Solubility of solids in Liquids

+

A concentrated solution contains a

high proportion of solute.

A dilute solution contains a small

proportion of solute.

A solution is called saturated when no

more solute can be dissolved in it.

Solubility of solids in Liquids

+

The concentration of solute in a

saturated solution is the solubility of

the solute at that temperature.

The solubility of most solids increase

with temperature.

Solubility

36

What is diffusion?

Diffusion is the random

movement of particles that

causes them to spread out and

mix with other particles.

37

Diffusion

Diffusion is a process by which particles of matter move from a region of higher

concentration to a region of lower concentration.

38

EXAMPLE

For example, the smell of

aftershave or perfume diffuses

and is detected by people on

the other side of a room.

39

Factors affecting Diffusion

#1: Temperature

The higher the temperature,

the faster the particles move,

the faster the rate of diffusion

40Factors affecting Diffusion

#2: Mass of particles

The smaller the mass,

the faster the particles diffuse

41Rate of diffusion

cotton

wool

soaked in

ammonia

gases

meet

here

cotton wool

soaked in

hydrochloric

acid solution

In this experiment, two gases diffuse towards

each other in a sealed glass tube.

When the gases meet, they

react and form a ring of

ammonium chloride, which is

closer to one end of the tube

than the other. Which gas

particles diffuse faster?

43

The ammonia particles have

travelled further down the tube

so they must have diffused at a

faster speed.