LSC S1:Matter

Matter, In this chapter, you should be able to:
a) understand what matter is and identify different states of mater.
b) use knowledge of kinetic theory and particulate nature of matter to explain the states of matter and
their properties.
c) know the factors that affect the rate of diffusion of a gas.
d) use scientific knowledge of the particle theory to
explain common phenomena such as gas pressure, clothes drying, rain formation and making a cup of tea.
e) understand the processes of change of state such as melting, boiling, evaporation, condensation, freezing and sublimation in terms of either heat gain or heat loss.
f) compare physical and chemical changes.
g) categorise processes in everyday life as physical and chemical changes.

Key words
condensation
diffusion
evaporation
freezing
melting
motion
sublimation
vaporisation

INTRODUCTION

When you wash your uniform, it dries quickly on a windy day, when preparing tea, the tea leaves spreads uniformly in hot water. Why? In this chapter, you are going to learn about matter and what brings about changes of states of matter.
A Gas moves from one place to another. Daily examples that illustrate the movement of particles of matter are the scent of food being cooked, perfume and smell of rotting rubbish. What factors affect the rate of movement of the particles? You will also learn about physical and chemical changes. In this chapter, you will appreciate and relate properties of states of matter to physical and chemical phenomena in daily life.
4.1 : Meaning and States of Matter
At the Primary school level, you studied about matter; the different states of matter and their properties. Do you still remember?
In Aactivity 4.1, you will recall about the states of matter.

What you need: notebooks, stylus, slate, and perkins brailler, braille papers, classroom and school compound.
What to do: In small groups:

1. Look around you, outside or inside your classroom.
   a) Name some of the objects you can smell, touch or see, feel observed?
   a) What are the different states of the substances you have collected?
   b) Classify the objects according to their physical state.
2. Discuss about matter and its states. Use the following guiding questions.
   a) Air is all around us, what is the physical state of air?
   b) Discuss the meaning of matter. In your own words, explain what is meant by the term matter.
   c) Matter can exist in three main states. How are the states of matter important to you or the society?
3. Compile a report and present to the rest of the class.
   At the primary school, you learnt about 3 states of matter. Did you know there is a fourth state of matter called plasma? Plasma is formed when a gas is heated to a very high temperature. Plasma can conduct electricity therefore, can be used to make flat screen television and laptop screens. Actually stars exist in plasma form.

At the primary school, you learnt about 3 states of matter. Did you know the a fourth state of matter called plasma? Plasma is formed when a gas is heat a very high temperature. Plasma can conduct electricity therefore, can be us make flat screen television and laptop screens. Actually stars exist in plasma
Properties of Matter
In activity 4.1 , you learnt that matter is anything that has mass and occupies s
What are the different states of matter? What are the properties of these of matter? Do activity 4.2 and 4.3 to discover the properties of matter.

Activity 4.2: Findina out about the properties ot solids and liquids
What you need: sand, water, 2 cups, notebooks, stylus, slate, and perkins brailler, braille papers, empty up and sand.
What to do: In small groups:

1. Lift an empty cup.
2. Half fill the second cup with sand and lift it up.
3. What do you notice?
   Task:
   I. Which property of matter is under investigation in steps (1) and (2).
4. Design an investigation to find out if liquids like water also have the same
   property you have identified in (1)?
5. List other properties of solids and liquids.
6. Write a report or braille your findings and present to the rest of the class.
   Liquids and solids have some properties which are similar, as well as those which are different. Properties of Gases
   In petrol stations car tyres are usually filled with air. Which property of gasses allow them to fill car tyres? Perform activity 4.3 to find out.

Activity 4.3: Finding out about sonne properties ot gases
What you need: a balloon, a thread, notebooks, stylus, slate, and perkins brailler and braille papers.
What to do:

1. Blow a balloon to fill it with air as shown in Figure 4.1.
2. Try to press the balloon as show in Figure 4.2 .

Group Discussion:
Form small groups and discuss about properties of matter. Use the following guiding questions:

1. Which properties of gases have you been investigating in this Activity?
2. List other properties of gases.
3. Have you ever tried to compress the gas in a syringe or in a bicycle pump, as shown in Figure 4.3? Why do you think you can h as?

4. Explain the differences in the properties of soli s, Liquids and gases
5. Write or braille your findings.
   Gases can be compressed, because their particles can be forced closer together. This property of gases is important when making an oxygen tank for scuba diving.

4. Explain the differences in the properties of solids, liquids andf gases
5. Write or braille your findings.
   Gases can be compressed, because their particles can be forced closer together.
   This property of gases is important when making an oxygen tank for scuba diving.
   4.2: Kinetic Theory of Matter
   Particles in matter are held together by forces of attraction. The strength of this force determines the way the particles move and how close they are to one another, as shown in Figure. 4.4. The strength of the force of attraction determines the state of a given matter.

In solid, the particles are closely packed, the forces of attraction between the particles are very strong, this explains why solids have a regular shape. In liquid state, the particles are far apart, therefore liquids have no fixed shape. What of in gases?
Changes of States of Matter
At home when boiling water, you have ever noticed hot vapour above the boiling water. Which process led to the formation of the vapour? In activity 4.4, you will learn about changes of states that take place during some physical processes.

Activity 4.4: Demonsttating changes 01 states of matter
What you need: Ice, nnotebooks, stylus, slate, and perkins brailler, braille papers, source of heat, water vapour, ice (solid water) and liquid water.

What to do:
In small groups, discuss about change of states of matter and do this Activity.

1. Your teacher is going to provide you with ice.
   a) Touch or observe the ice. Note the physical state of ice?
   b) Leave the ice in a warm place for 10 minutes. Note the physical state after 10 minutes. Describe the change of state that took place. (Use the hint in Figure 4.5).
2. The Picture in Figure 4.6 shows what happens when Iodine is heated and the vapour cooled using ice and Figure 4.7 shows changes of state when liquid water is boiled in a kettle and the vapour cooled.

Change in states of matter is caused by temperature variations. When you heat a solid substance like ice, it changes into liquid water by the process of melting, see figure 4.8. When liquid water is boiled, it turns into vapour by the process of evaporation.

The water vapour can be reversed back into liquid water by cooling, a process called condensation.

However, some solids for example ammonium chloride and iodine when heated, changes directly to vapour by a process called sublimation. (See figure 4.8). When vapour of such solids is cooled, they directly change to solids by a process called deposition.
Figure. 1.8: Changes of state of water and iodine
Evidences supporting the Kinetic Theory of matter The Kinetic Theory of Matter states that particles of matter are in constant motion. This theory can be supported by evidence of diffusion and Brownian motion.
4.3: Factors that Affect the Rate of Diffusion of a Gas
When chicken is being fried in the kitchen, after sometime you are able to smell it from far. How does the smell move from its source in the kitchen to your nose? It spreads by the molecules moving from their region of high concentration to their region of low concentration. This process is called diffusion.

Activity 4.5: Demonstrating diffusion in gases
What you need: slate, stylus, perkins brailler, braille papers and perfume.
What to do:

Hint: – Do not spray the perfumes directly to the nostrils or smell directly. Do it in a well ventilated room.
Can diffusion occur faster in liquids compared to air? What is your prediction? Perform
Activity 4.6 to learn about diffusion in liquids.

a) What was the observation? See Figure. 4.10.
b) Predict the observation when you use gel in place of water.
c) Can similar results be obtained?
d) Explain your observation(s) using the Kinetic Theory of matter.

2. In your everyday life, in which situations do you apply the principles of
   diffusion in liquids?
3. Compile a report of your findings.
   Caution: Wash your hands with clean water after the Activity.
   Diffusion takes place faster in gases than in liquids. Why? The particles of a gas have very weak forces of attraction between them compared to liquid particles. The particles of gases move faster than those in solid state. Therefore, diffusion occurs faster in gases than in solids and liquids.

Brownian Motion
When sitting in an iron roofed house on a sunny day, and the iron sheets have holes, you will observe dust particles moving randomly in the rays of the sun. Why do they randomly move?

Activity 4.7: Discussing about Brownian motion
What you need: notebooks, stylus, slate, and perkins brailler and braille papers.
When you are on dusty stage night with the stage at light on as shown in Figure 4.11 (a) or a car with headlamp lights on being driven on a dusty murram road at night, as shown in Figure.4.11 (b). You would observe the dust particles moving randomly. The random movement of the dust particles in these situations is described by Brownian motion.

What to do:

1. Explain the observations shown in the Figure 4.11. Hint: Use the Kinetic Theory of matter
2. Using your own words, describe Brownian motion.
3. Give three examples of situations in your daily life where Brownian motion can be observed.
4. Explain the behavior of matter according to Brownian motion.
5. Compile a report and present to the rest of the class.
   Air is made up of invisible particles in constant random motion.
6. 4.4: Daily Phenomena
   Some occurrences that take place in our everyday life, can cause you to wonder and ask questions. Daily events such as drying of clothes, gas pressure, rain formation and making a cup of tea. Which other daily phenomena makes you to wonder? These daily events can be explained by using knowledge of particle and kinetic theory. Clothes drying faster when there is sun shine and when it is windy When you have wet laundry that just got washed. You want to dry the clothes as quickly as possible but only have the option of hanging up the clothes to dry. Would it be quicker to dry the clothes by hanging them indoors or outdoors?

Activity 4.8: Exploring what can make a wet piece of cloth to dry taster
What you need: Internet if available, notebook, stylus, slate, perkins brailler,
braille papers, water and paper or cloth.
What to do
1.Form small groups, and discuss how you can make a cloth to dry faster.
2.Explain why a wet piece of cloth dries faster on:
e) Hot still (windless) day than a cold day.
f) Cold windy day than cold still day.
3.If you place your wet handkerchief near to a working fan, will it dry faster
than a handkerchief in a similar room without fan? Explain your answer.
4. When sitting in a room on a hot day, or when sweating of after performing
a vigorous exercise, people tend to switch on a fan. Why do they do so?
5. Compare your findings with that of other groups.

Gas Pressure
In primary science, you defined pressure as force per unit area. In our daily lives, you have ever wondered, why a car is able to carry a heavy load of goods or what makes a basketball remain spherical.
In Activity 4.9 you will be able to understand why that is possible.

Activity 4.9: Demonstrating gas pressure
What you need: A balloon and piece of thread, notebooks, stylus, slate, and perkins brailler and braille papers. What to do: In pair,

1. Blow a balloon to fill it with air.
2. Tie the mouth of the balloon with a piece of thread.
3. Press or squeeze the balloon as shown in Figure. 4.12. What
   do you feel?
4. Describe any three daily Figure. 1.72: I applications of gas pressure in your life.
5. What does gas pressure tell you about matter in the gaseous state?

Particles of gases are in constant random continuous motion. They knock and bounce off each other and the inside of the container producing gas pressure. Gas pressure is the force produced by gas particles knocking against the inside of the container.
Similarly, when you press a balloon, you are exerting pressure on the balloon. The gas pressure resists the balloon from being pressed. The same explanation holds for a bicycle tube supporting the bicycle and its load. How fast tea leaves dissolve in cold water and in hot water

Activity 4.10: Discovering how fast tea leaves dissolve in cold water and in hot water
What you need: notebook, stylus, slate, perkins brailler, braille papers, hot water, cold water, hot water, tea leaves, two cups and tea spoon
What to do: Watch or listen to the animation or simulation on solids dissolving in cold water and in hot water.
Group Discussion:
I. Form small groups, discuss and:
a) List some of the substances you dissolve in water during your day to day activities.
b) What do you need when you want to prepare a cup of tea?
c) What steps do you take when preparing a cup of tea?
d) Explain why tea leaves spread faster in hot water than in cold water.

2. Hassan and Mary were preparing rice. They added three table spoons Of salt to the water. When they tasted the water the salt was just enough but when they tasted the rice when cooked, they realised the salt was too much. Explain why this was so.
3. Compare your findings with those of other groups.
   Sugar spreads faster in hot water than in cold water. Two spatula end full of sugar can completely dissolve at 250C in 3 minutes. But, two spatula end full of sugar can completely dissolve at 10000 in one minute and 30 seconds.
   When salt is used, about the same amount of salt remains at the bottom of both the hot and cold solvent. Only a little more salt can dissolve in very hot water than in cold water. Why?

4.5: Effects of heat on changes of states of matter
When preparing beef stew at home, one of the steps is placing cooking fat in a saucepan placed on a charcoal stove/or gas or firewood to melt the fat. Does the cooking fat absorb or release heat?

Activity 4.11: Exploring heat changes during change of states of matter
What you need: Ice, saucepan, thermometre, sodium hydroxide pellets, test tube, distilled water and source of heat, notebooks, stylus, slate, and perkins brailler and braille papers Sodium hydroxide is a highly corrosive chemical, so handle it
A CAUTION
with care, Wash your hands with soap and clean water,
What to do: In pairs:
I. Place a spatula end full of sodium hydroxide pellets in a test tube.
2.Add 5 cm3 of distilled water to the test tube. Feel the test tube with your
hand. Note the observation. Is heat given out or absorbed? Give reasons. for your answer.
3. Put some ice in a saucepan.
4. Place the saucepan over a flame. What happened to the ice?
5. Mention physical or chemical changes in your everyday life. State whether the changes absorb of release heat.

In order to convert solid to liquid, and liquid to gas the inter-particle force of attraction must be broken, This process requires heat energy therefore energy is required, Examples of such reactions are melting and evaporation. On the other hand processes like condensation and freezing release heat energy.
After shaving your hair, the barber usually applies methylated spirit on your skin.
What do you notice? Why does methylated spirit feel cold on your skin? In Activity 4.12 you will learn about heat changes by your body. Activity 4.12: Discussing the cooling effect of evaporation on our body
What you need: notebook, stylus, slate, perkins brailler, braille papers, sunlight, source of heat, water and sauce pan.
What to do: In small groups:

1. Discuss whether evaporation absorbs heat energy or gives out heat energy.Give reasons for your answer.
2. Describe the importance of evaporation in preventing the body from overheating on a hot day.
3. Where does sweat on your skin get the heat energy to vapourise?
4. Explain some of the application of this in your daily life.
5. Write or braille your findings and present to the rest of the class.
   Evaporation causes cooling because the process requires heat energy. The energy is taken away by the particles as they convert from liquid into gas, and this causes cooling on the surface.

4.6: Physical and Chemical Changes
During our everyday activities, changes take place; for example: rainy season art sunny season, day and night, among others. Some of these changes are and irreversible while others are temporary and reversible.
Activity 4.13: Classifying changes jn your daily life as permanent or temporary
What you need: notebooks, stylus, slate, and perkins brailler, braille papers, source of heat, ice water, sauce pan, sugar, salt, cup, paper, matchsticks and charcoal or firewood The picture in Figure 4.13 shows your sister boiling rice on a firewood stove at night,
the source of light is a burning candle. Near the stove, there is a pile of fruits, the fruits have started to ripen. Your mother is making tea by dissolving sugar in hot water Hanging from the roof is a pot containing a growing flower. Discuss the picture.

What to do:
1. Identify the physical and chemical changes shown in Figure 4.13.
2.Explain how the changes you have identified are important to you..
3.Categorise the processes you have identified from Figure 4.13 as physical or chemical changes.
4.Compare physical and chemical changes.
5.Write or braille you finding individually and submit to the teacher for evaluation.

By definition, a temporary change (physical change) is a type of change where a new substance is formed. A permanent change (chemical change) is a type of change where no new substance is formed.
Is rusting a permanent change or a chemical change?
Look at figure 4.13, you will see iron nails and car body that have rusted. Can you name other things in our daily life that can rust? Rusting is a slow process that requires more than two days to take place. The brown coat that forms on iron material is called rust. The chemical name of rust is hydrated iron (Ill) oxide.

Is rusting of a permanent change or temporary change? Do the next activity to find out.
Activity 4.14: Finding out whether rusting of an iron nail is a permanent Of temporary change
What you need: notebooks, stylus, slate, and perkins brailler, braille papers
and nails.
What to do:

1. In small groups, plan and design an investigation to find out whether rusting of an iron nail is a temporary change or a permanent change.
2. Write or braille a practical report for this investigation showing:
   a) Requirements under sub-headings: reagents and apparatus
   b) Steps followed in their correct order
   c) Results and interpretation
3. Mention the disadvantages and one advantage of rusting?

4.7: Physical and Chemical Changes in Everyday Life
Activity 4.15: how permanent and tetnpotary changes are in your lite
What you need: notebooks, internet connection, slate, stylus, perkins brailler and braille papers.
What to do

1. Divide into two groups in your class or stream with one group being the opposers and the other group proposers.
2. Debate the motion “Temporary changes are more important than permanent changes in our life. “
3. Compile the findings from the debate. Write or braille them in your notebook.
   A temporary change means that a substance that was heated and cooled can be obtained again; and a permanent change means on cooling the substance heated cannot be obtained again.