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Chapter 1 Solids,

Liquids & Gases

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Lesson Objectives To describe the main properties of solids, liquids and gases

To describe and explain evidence for movement of particles in liquids and gases

To explain everyday effects of diffusion in terms of particles

To state qualitatively the effect of particle mass on the rate of diffusion

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What is a matter?

• Can you name me some matter in this room?

Matters are anything that have mass and take up space

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What are the states of matter?

• How many states are there?

• What are they?

3 states

Solid, Liquid and Gases

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How many states in this glass ?

Solid

Liquid

Gas

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Solid Liquid Gas

Hard and dense Not hard butdense

Not dense

Fixed shape No fixed shape No fixed shape

Cannot be compressed

Cannot be compressed

Can be easily compressed

Fixed volume Fixed volume No fixed volume

Do not flow Flow easily Flow in all directions

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Kinetic Particle Theory

• Matter is any substance that occupies spaceand has mass.

• Matter exists as

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Matter are made up of tiny particles:

1. These particles are too small to be seen

2. There are spaces between the particles

3. Particles are in constant motion

Kinetic particle theory of Matter:Matter are made up of particles and these particles are too small to be seen directly There are spaces between the particles Particles are in constant motion

Diffusion:Diffusion is the spreading and mixing (movement) of particles in liquids and gases The higher the temperature, the faster the molecules move, the faster is the diffusion.The smaller the mass, the faster they move, the higher the rate of diffusion.

Summary

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Particulate

Model of Matter

Lesson Objectives To describe the kinetic particle model of solids, liquids and gases

To use particulate model to explain the behavior and properties of matter

To explain the interconversion of states of matter in terms of the kinetic theory and of the energy changes involved

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Solid• Arrangement

– Orderly

– Closely packed

• Forces between particles– Very strong

• Particle Kinetic Energy– Very Low

• Particle motion– Vibrate and rotate about a fixed

position

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Liquid• Arrangement

– Disorderly

– Less closely packed

• Forces between particles– Strong

• Particle Kinetic Energy– Low

• Particle motion– Slide over each other

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Gas• Arrangement

– Disorderly

– Very far apart

• Forces between particles– Very weak

• Particle Kinetic Energy– High

• Particle motion– Move around at high speed

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Having the physical properties in mind, what will you think the arrangement and movement of particles will be?

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Solid Liquid Gas

Drawing the particulate diagram for different states

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Density

• Look at the particle models again…

• Which state has highest density?

Solid (ice) Liquid (coke) Gas (carbon dioxide)

Density Highest Mid range Lowest

Liquid has fewer particles than an equal volume of solid, similarly gas has fewer particles and the particles are further apart than the particles in the same volume of liquid or solid. Therefore density of gas (mass per volume) is lowest.

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Solid Liquid Gas

Can you see the difference?

Particle diagram

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Particles in a solid – animation

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Particles in a liquid – animation

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Particles in a gas – animation

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Solid Liquid Gas

Arrangementof the particles

Particles are very closely packed together in an

orderly manner

Particles are closely packed together in a

disorderly manner

Particles are far apart in

randomarrangement

Quick review

Particulate Theory of Matter

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Solid Liquid Gas

Attractive

Forces

Particles held together by

strong forces

Held together by strong forces

(weaker than

that of solid)

Not held together by

strong forces

Solid Liquid Gas

Movement of the

particles

Vibrations about fixed positions

Randommovement

throughout the liquid

Movement anywhere

Attractive Forces

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Next lesson…

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• Please read textbook pg 44-49 – Changes of states.24

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Solid Liquid Gas

Drawing the particulate diagram for different states

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Changes of

State…

Change of states

Boiling

Condensation

Lesson Objectives

To observe the differences in the changes between the 3 states of matter

To use particulate model to explain the changes of matter

To explain the interconversion of states of matter in terms of the kinetic theory and of the energy changes involved

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Changes of states

• Particulate model of matter can explain the changes of state.

• What happen when a solid is heated?

Let view the animation…

Melting• When a solid is heated…

Particles in it gain energy and vibrate more.

As temperature increases, vibrations increases until they are able to overcome the forces that hold them in their fixed positions.

The temperature at which a solid melts is called the melting point.

The temperature remains constant at the melting point because the heat absorbed is used to overcome the attractive forces between the particles.

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Boiling• When a liquid is heated…

Particles in it gain energy.

As temperature increases, particles move more quickly and eventually have enough energy to completely break the forces that hold them together.

Particles then move freely and far apart.

The temperature at which a liquid boils is called the boiling point.

There is no change in the temperature at this point.

• The temperature is constant because heat absorbed is used to break all the forces holding the particles together.

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Change of states

http://www.footprints-science.co.uk/flash/states.swf

Heating Curve

A

B

C

D E

Mixture of solid and liquid

Mixture of liquid

and gas

Reading the Heating Curve 1

Graph shows how temperature of substance changes with time during

melting when it is heated steadily.

1. AB - the substance is completely ______________.

2. Point B - ____________ begins at _______________________.

( The first drop of ________ appears).

3. BC - ________ continues to take place. The substance

exists as a ________ of _____ and __________.

4. Point C – The last drop of _________ is formed.

5. CD – The substance is completely __________

( )

melting

solid liquid

liquid

molten

liquid

liquid

mixture

solid

melting

the melting point

Think……

Why does the temperature remain constantbetween B and C even though heat is continuously supplied?

Ans: The heat is used to overcome the forces of attraction holding the solid particles instead of causing the temperature to rise.

Reading the heating curve 2

Graph shows how temperature of substance changes with time during

melting when it is heated steadily.

1. CD - the substance is completely ______________.

2. Point D - ____________ begins at _____________________.

( The first drop of ________ appears).

3. DE - ________ continues to take place. The substance

exists as a ________ of _____ and __________.

4. Point E – The last drop of ________change into

_________ state.

5. Beyond E – The substance is completely __________

liquid

boiling the boiling point

gas

boiling

mixture gas liquid

liquid

gaseous

gaseous

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Condensation• When a gas is cooled…

Particles in it loses energy; move more slowly.

The forces of attraction between the particles will pull the particles closer to each other, eventually forming a liquid.

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Freezing• When a liquid is cooled…

Particles in it loses energy; move more slowly.

Temperature decreases until freezing point is reached.

At freezing point, the liquid turns into a solid.

Temperature stay constant while liquid freezes because heat energy is released when particles slowed down to take up their fixed positions in the solid.

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Cooling Curve

temperature remains constant

freezing completes

freezing starts

freezing point

(=melting point)

SOLID

LIQUID + SOLID

LIQUID

temperature (ºC)

time from start (min)

P

Q R

S

Reading a graph on freezing

Graph shows how temperature of substance changes with time during

melting when it is heated steadily.

1. PQ - the substance is completely ______________.

2. Point Q - ____________ begins at _____________________.

( The ______ drop of liquid begins to form a ______).

3. QR - ________ continues to take place. The substance

exists as a ________ of _____ and __________.

4. Point R – The last drop of _________ will change into a ______

5. RS – The substance is completely __________

liquid

solid

the freezing point

first

freezing

freezing

mixture liquidsolid

liquid solid

solid

Think……..

Why does the temperature remain constantbetween QR even though the substance is continuously cooled?

Ans:

During cooling heat is given out by particles as they take up fixed positions is equal to heat loss from the surround during cooling.

Sublimation• When solids change into gases without melting.

Examples:

- Solid carbon dioxide changes to a gas at -78°C

- Iodine

- Ammonium chloride

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Evaporation• When liquids turn into gases without boiling.

• Evaporation occurs below boiling point of liquid.

Difference between boiling and evaporation?

Evaporation only takes place at the surface of liquid, at any temperature and is very slow.

Boiling takes place throughout the liquid, only at boiling point and is usually faster.

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Practice Question Practice Questions