7C2 Particles

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• Particle theory
• Movement of particles
• Change of state
• Pure substances and mixtures
• Solubility

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5 Quick Questions

Zooming in

• Draw what you think you could see if you could zoom in to have a look at the nails even closer than a microscope can.

Daltons model (1803)

John Dalton thought that all matter was made of tiny particles called atoms, which he imagined as tiny solid balls. Dalton’s model included these ideas:

• atoms cannot be broken down into anything simpler
• the atoms of a given element are identical to each other
• the atoms of different elements are different from one another
• during chemical reactions atoms rearrange to make different substances

Solid, liquid or gas

Label the solids, liquids and gases - S, L or G.

The particle model

• We use models in science to help up explain difficult concepts
• The particle model is our model for how the particles in solids, liquids and gases behave.
• All substances are made up of particles.
• Particles are tiny, you cannot see them with the naked eye.
• In a pure substance, all of the particles are the same.
• Particles do not change when the state of matter changes – water particles in ice are the same as the ones in water and steam.

Solids, liquids and gases

• Imagine the balls in your tray are the particles of a pure substance in a closed container.
• Use the balls in your tray to model the arrangement and movement of the particles as a solid, a liquid and a gas.

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Then, answer all the questions on pages 49 – 51.

Answer the questions 1 – 6 on pages 50 - 51

Practical Task

• Look at each of the samples around the room.
• Do not open the containers.
• Complete the results table on page 52.
• You need to observe each of the materials and decide whether you think they:
• Have a fixed shape
• Have a fixed volume
• Can be poured
• Can be squashed
• Is a solid, a liquid or a gas
• Then complete the summary table at the top of page 53

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How can you tell if it is a solid?

Can it be compressed?

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Can it flow?

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Does it have a fixed shape?

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Does it have a fixed volume?

How can you tell if it is a liquid?

Can it be compressed?

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Can it flow?

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Does it have a fixed shape?

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Does it have a fixed volume?

How can you tell if it is a gas?

Can it be compressed?

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Can it flow?

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Does it have a fixed shape?

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Does it have a fixed volume?

Complete the wordfill on page 53:

• Solids, liquids and gases are all different states of matter. We can tell the different states of matter apart by looking at how the behave in certain ways – also known as their properties.
• In science, we say that solids have a fixed volume and shape, they do not flow and cannot be squashed or compressed.
• Liquids have a fixed volume and take the shape of their container. They do flow but cannot be compressed.
• Gases take the shape and volume of their container. Gases are able to flow and can be squashed or compressed.

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Squashed Container Gases Flow

Liquids States Properties

Volume Compressed

• Solids, liquids and gases are all different states of matter. We can tell the different states of matter apart by looking at how the behave in certain ways – also known as their properties.
• In science, we say that solids have a fixed volume and shape, they do not flow and cannot be squashed or compressed.
• Liquids have a fixed volume and take the shape of their container. They do flow but cannot be compressed.
• Gases take the shape and volume of their container. Gases are able to flow and can be squashed or compressed.

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True or False?

• The different state of matter are solids, liquids, gases and slime?
• Solids have a fixed volume.
• Liquids can be compressed.
• Gases take the volume and shape of their container.
• Solids can flow.
• Liquids can flow
• Liquids take the shape of their container.
• Gases cannot be compressed.

FALSE

TRUE

FALSE

TRUE

FALSE

TRUE

TRUE

FALSE

How are particles arranged in solids?

Particles form a regular shape with a fixed volume.

All particles touching other particles.

Particles cannot move around, just vibrate.

Particles do not flow – they cannot move.

Particles cannot be compressed – there is not space to move into.

Copy or summarise this information in column 2 of the table on page 54.

How are particles arranged in a liquid?

Particles are touching other particles around them.

Particles have a fixed volume.

Particles are able to move over each other – this is why liquids can flow.

Liquids cannot be compressed. There is no space between the particles for them to go into when put under pressure.

They always take the shape of their container.

Copy or summarise this information in column 2 of the table on page 54.

How are particles arranged in a gas?

Particles move around freely and spread far away from each other.

As they have a lot of space between them, more particles can be added to a space, so gases can be compressed.

Take the shape and volume of their container – for example a balloon.

As gas particles are able to move around each other, they are able to flow.

Copy or summarise this information in column 2 of the table on page 54.

Explaining the properties - The particle model

The particles in solids, liquids and gases have forces of attraction between them.

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These forces are different between the molecules of a substance in the different states.

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Explaining the properties - The particle model

Solids have very strong forces of attraction between the particles. The forces of attraction are SO STRONG that the particles are touching and fixed in place.

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Copy or summarise this information in column 3 of the table on page 54.

Explaining the properties - The particle model

In liquids, the forces are MODERATE, keeping the particles touching, but allowing them to move from place to place.

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Copy or summarise this information in column 3 of the table on page 54.

Explaining the properties - The particle model

Gases have weak forces of attraction between particles

The force is weak enough to allow the particles to move around away from each other.

Copy or summarise this information in column 3 of the table on page 54.

Part 3

• Answer the questions on page 55.

B or C

A

Random order

Particles fill the space

Particles all the same

Particles not touching

Doesn’t show movement of particles

Fills whole container, not just the bottom

7C2 Particles

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• Particle theory
• Movement of particles
• Change of state
• Pure substances and mixtures
• Solubility

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Answer the starter question on page 56

Lesson Outcomes:

Brownian Motion

• Particles in both liquids and gases (collectively called fluids) move randomly. This is called Brownian motion. They do this because they are bombarded by the other moving particles in the fluid. 

Answer the questions in concept 2a on pages 56 & 57

A

B & D

A, B & D

A

• Smoke Cell - YouTube

Diffusion

• Diffusion is the movement of a substance from an area of high concentration to an area of lower concentration. Diffusion occurs in liquids and gases when their particles collide randomly and spread out

Answer the questions in concept 2b on page 57

Ammonia chloride

• The reaction of ammonia and hydrogen chloride demonstration
• Video on silent from 2:00 – 3:30
• Video

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• Can you explain what happened?

Answer the questions in concept 2b on pages 58

Diffusion is the _________________ of particles from an area of ________ concentration to an area of low concentration.

Particles in a liquid or a gas have a relatively weak force of _______________ between them. This means that they can move.

The particles spread out in a random way until they are ____________ spread out. The particles continue to move but remain evenly spread out.

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evenly movement high attraction

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high

evenly

attraction

movement

Gas pressure

List as many objects you can that are filled with air.

Blowing up a balloon

Bumping particles

The particles in a gas move quickly in all directions, but they don't get far before they bump into each other or the walls of their container.

When gas particles hit the walls of their container they exert a force called gas pressure. The more particles that hit the walls, the higher the pressure.

This is why the pressure in a tyre or balloon goes up when more air is pumped in.

Task 1

Draw a balloon before and after inflating .

Show the particles in the both diagrams and explain why the balloon gets bigger as it is inflated.

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Key words: collide, force, gas pressure, move, particles.

Quiz

8C2 Particles

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• Particle theory
• Movement of particles
• Change of state
• Pure substances and mixtures
• Solubility

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Water

• What are the different states of matter for water?

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SOLID

LIQUID

GAS

• Get out your homework books.
• C1, Particles, pages Your next homework is and spend a couple of & 15 – it’s due on 24^th November – write this date on the front of your homework books.
• Spend the next couple of minutes revising your 7B1 core questions, ready for your test.

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Changes of State

• Ice, water and steam are all made up of the same type of particles – they are arranged in different ways.

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Changes of State

SUBLIMATION

• The particles can change from one state to another. When they do this, the particles rearrange and behave differently.

BOILING

What happens when a solid melts?

• When a solid is heated, it melts and changes into a liquid – the particles start to vibrate more and move over each other. The particles lose their fixed shape and take the shape of the container.

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What happens when a liquid boils?

• When a liquid is heated and changes into a gas – the particles move around more and spread apart. The gas particles are able to move around very fast and spread out to fill the container.

What happens when a gas condenses?

• When a gas cools down and condenses, the particles slow down and come closer – changing to a liquid.

less

heat

less

heat

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What happens when a liquid freezes?

• When a liquid cools down further and freezes, the particles are not able to move around each other and take a fixed shape.

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less

heat

less

heat

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Bunsen Burner

Labelling a Bunsen Burner

Flame

Air Hole

Base

Chimney

Collar

Reding a thermometer

What temperature is shown on each of the thermometers?

1. ___^oC 2 . ___^oC 3 . ___^oC 4 . ___^oC 5 . ___^oC

Observing and Mass change during changes of state�

Collect:

• A balance
• A 100 ml beaker
• A thermometer
• A tin can
• A Bunsen burner
• A tripod
• A gauze
• A heatproof mat

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Observing and Mass change during changes of state�

Method:

• Weigh a 100ml glass beaker on a top pan balance. Record your result in the table on page 155. (A)
• Add a handful of crushed ice to the beaker and reweight it. Record your result.(B)
• Calculate the mass of the ice. (C)
• Stir your thermometer in the crushed ice and note its temperature.
• Place your tin can onto the heatproof mat and half fill with hot water from a kettle.
• Stand your beaker in water bath to melt the ice.
• Keep watching the temperature as the ice melts and record the temperature of the change of state in the results table. You should also record anything interswting you notice (your observations)

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How to light a Bunsen burner

1. Connect the Bunsen to the gas tap
2. Close the air hole
3. Light a splint (from another Bunsen burner)
4. Walk carefully back to your desk
5. Hold your splint over the chimney
6. Turn the gas tap on
7. Stub the splint out on the mat

Hottest

part

If the Bunsen burner goes out you must turn off the gas IMMEDIATELY

Observing and Mass change during changes of state�

Method:

• Dry the outside of your beaker and reweigh the beaker and water. Record your result. (D)
• Calculate the mass of water (E).
• Place your beaker on a tripod and heat gently.
• Keep putting the thermometer into the water and record the temperature as the water changes state.

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Melting and boiling water experiment

The temperature stayed the same as the ice melted

1. Bubbles

2. The temperature stayed the same as the water boiled

0^oC

100^oC

If you didn’t get these numbers your experiment wasn’t very accurate, but don’t change your results, make a note of what the result should have been.

Questions

Answer the questions on pages 62 – 64.

Melting

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Boiling

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Bubbles (of water in the gas state)

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Smaller volume of water / steam

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The mass does not change when the water melts

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Questions

The water would have evaporated into the air and we would not be able to put it on a balance.

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Questions

1

4

2

5

6

3

Questions

7C2 Particles

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• Particle theory
• Movement of particles
• Change of state
• Pure substances and mixtures
• Solubility

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5 quick questions

Pure substance

What does pure mean?

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In everyday life – ‘pure’ means that nothing has been added.

In science – ‘pure’ means that there is only one type of substance is present.

Mixture

Mixture

Pure

Pure

Examples of Pure Substances and Mixtures

Mixtures

Pure Substances

Haribo

Diamond

Air

Oxygen – One of the particles in air.

Particles in a pure substance.

• Pure substances are made up of only ONE type of substance
• All of the particles in a pure substance will be the same – either the same single particle or the same types of particle joined together.

This pure substance is made up of only one type of particle.

Is this a pure substance? They all look the same – and they are made up of the same particles. So yes, they are a pure substance.

Particles in a mixture.

• A mixture is made up of two or more substances that are not joined together and are easily separated.

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Copy and complete the Word fill:

In science, a pure substance is one that is made up of only one element or compound. Elements cannot be broken down into smaller parts and compounds are not easily separated.

A mixture is made up of two or more substances that are not joined together. A mixture can contain different types of elements, compounds or a mixture of both. Unlike compounds, mixtures can be easily separated into its different parts.

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Mixture Compounds One Science Joined Separated Elements Easily

In science, a pure substance is one that is made up of only one element or compound. Elements cannot be broken down into smaller parts and compounds are not easily separated.

A mixture is made up of two or more substances that are not joined together. A mixture can contain different types of elements, compounds or a mixture of both. Unlike compounds, mixtures can be easily separated into its different parts.

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Look at the diagrams below and answer the questions using full sentences:

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1. Which of the three samples is made up of only one type of substance? How can you tell?

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• Which of the three samples is made up of more than one type of substance joined together?

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• Which of the three samples is made up of more than one type of substance that is not joined together?

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• Which of these will be easiest to separate? Why?

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Pure Substances and Mixtures

Sample A

Sample B

Sample C

Look at the diagrams below and answer the questions using full sentences:

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1. Which of the three samples is made up of only one type of substance? How can you tell?

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2. Which of the three samples is made up of more than one type of substance joined together?

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3. Which of the three samples is made up of more than one type of substance that is not joined together?

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4. Which of these will be easiest to separate? Why?

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Pure Substances and Mixtures

Sample A

Sample B

Sample C

Sample A – it only has one type of substance joined together.

Sample B – it has different particles joined together but they are all the same type.

Sample C – it has different types of particles that are not all joined together.

Sample C will be the easiest to separate as it is made up of lots of different particles that are not joined together.

7C2 Particles

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• Particle theory
• Movement of particles
• Change of state
• Pure substances and mixtures
• Solubility

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Practical order

5 quick questions

In pairs, discuss what will happen if I mix salt, sand and flour into the water in 3 beakers? �On your whiteboards: try to write a simple phrase to describe what will happen in each case.

sugar

sand

flour

State symbols

1. 3.

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solid gas

2. 4.

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liquid solution

(solid dissolved in water)

On your whiteboards: What do diagrams 1 – 3 represent?

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What do you think diagram 4 shows?

(s)

(l)

(g)

(aq)

State symbols

Complete this matching exercise on page 67

• What did we call the forces which keep the particles in a solid together?

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• Sometimes particles more attracted to other types of particles.

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When solid sugar is added to water, the sugar particles are more attracted to the water particles than to each other. So, we end up with the individual particles of sugar being surrounded by water particles.

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When this happens, we say that the sugar has dissolved into the water

Answer questions 1 – 4 on pages 67 - 68

Questions

Soluble substances

• There are special names for the substance that dissolves (sugar), the liquid that it dissolves into (water) and what the end result is (the sugary water).

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• Solute
• Solvent
• Solution

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Solutions will always be clear (you can see through them) and often, but not always, colourless (like water).

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Mixing water and ethanol

• How do you think the mass of the mixture comparer to the mass of the water and ethanol added together?
• A: Same
• More
• Less
• How do you think the volume of the mixture comparer to the volume of the water and ethanol added together?
• A: Same
• More
• Less

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Mass = Mass = Mass =

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Volume = Volume = Volume =

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Mass of solutions

• The total mass of the mixture made from a substance dissolving in a liquid will be exactly equal to the mass of the solid added to the mass of the liquid

Answer all the questions on pages 68 - 69

7B1 start here

• Check answers to questions on pages 68 - 69

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Insoluble substances

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• Substances that do not dissolve are called insoluble

Suspension

• Whether or not a substance is soluble or insoluble depends on the liquid that it is put in to. Just because something is not soluble in water it does not mean that it won’t dissolve if it is mixed with a different solvent.

Answer all the questions on pages 70 - 73