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The physical states of matter

At normal temperature almost all substances exist in one of three physical states:

liquids gases

solids

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Look at the following substances. Decide whether they exist as a solid, liquid or gas.

tree

cloud

ice lolly

oxygenbutter

orange juice

desk

bleach

coal

perfume

steam

shampoo

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Aluminium, argon, ethanol (alcohol), iron, lead, mercury, radium, tin

Liquid Metal

Solid used in aircraft

Solid used to coat steel cans

Intoxicating liquid

Radioactive solid

Solid that rusts

Un-reactive gas

Solid used by Ancient Roman plumbers

MMercury

AAluminium

TTin

EEthanol

RRadium

IIron

AArgon

LLead

Match each substance to the correct column in the table. When you have got it all correct the first letter of each substance will spell a word that is important in this unit.

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Kinetic Theory

The existence of solids, liquids and gases is

explained by the kinetic theory.

This is based on the following ideas:

1. All substances are made up of particles (atoms, ions and molecules).

2. That these particles are attracted to each other, some strongly and others weakly.

3. That these particles move around (i.e. have kinetickinetic energy).

4. That their kinetic energy increases with temperature.

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Particle arrangements: solids

This animation shows a 2-D view of the motion of the atoms in a 3-D solid.

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Particle arrangements: liquids

This animation shows a 2-D view of the motion of the atoms in a liquid. There is no order.

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Particle arrangements: gases

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Diffusion 1

• Diffusion is the movement of one type of particle into and through another. For example, the smell of after-shave or perfume diffuses across a room.

Can you explain these facts?• Diffusion occurs both in liquids and

gases but hardly at all in solids. • It happens more quickly for gases

than for liquids.• It happens more quickly at warm

temperatures than at cooler temperatures.

Insects communicate by smells that diffuse through the air.

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Diffusion 2

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Diffusion 3

Here is the result of a simple experiment in which two gases diffuse towards each other in a glass tube.

When they meet they react to form a cloud of smoke.

Cotton wool soaked in ammonia solution

Cotton wool soaked in hydrochloric acid (concentrated)

The smoke forms nearer to one end than the other.

Which particles are moving faster: ammonia or acid?

Can you suggest a possible reason for this?

Ammonia particles are lighter and so, at any given temperature, move faster.

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Crossword

Across:2 Change from liquid to solid5 Force caused by collisions

of particles6 Arranged in a 3

dimensional pattern9 Spacing of particles in

solids and liquids10 All substances are this

state at very low temperatures

11 Only liquids and gases do this

1

2 3

4

5

6

7 8

9

10

11

Down: 1 "Heavy“ 3 Change from gas to liquid 4 Change from solid to liquid 6 State with particles close but disorganised

7 Particles widely spread out 8 Change from liquid to gas

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1. Which of the diagrams represents a liquid evaporating?

BA DC

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A compressible, fluid

B non-compressible, fluid

C compressible, no fixed shape

D non-compressible, very low density

2. Which of the following describes a liquid?

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3. Which of these is only true for a gas?

A can flow

B exerts pressure on its container

C will occupy the whole of the container it is placed in

D has no shape of its own