Science Form 1 - Chapter 5
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CHAPTER 5
The Air Around Us 5.1
What is air made of State what is air made of Explain why air is mixture State the everage percentage of nitrogen, oxygen and carbon dioxide Carries out activities that shows: 1. The percentage of oxygen 2. That air contains water vapour, microorganisms and dust Click on page as long as red bullet still exist
All living things need air to live.We can fast for a day or two without taking any food or water, but how long can we live without air? Take a deep breath and hold it as long as you can. Then exhale onto your palm. Can you feel the air coming out from your nostrils? We cannot see the air but we know it is there. Earth is surrounded by 30 kilometres of air: a mixture of several different gases mixed together in different proportions. Unfortunately the air around us is becoming polluted by the day. Can we live in polluted air? What must we do to keep the air clean to save ourselves and the rest of the world?
What Is The Composition Of Air ? Air is a mixture of different gases. The pie chart shows the composition of air by percentage. What is the average percentage of nitrogen, oxygen, carbon dioxide and inert gases in the air? Why is the word ‘average’ used in the earlier question?
Oxygen 21% Nitrogen 78%
Carbon dioxide 0.03%
Inert gases <1%
Air as Mixtures As a mixture, the composition of air varies from place to place and time to time. Air also contains varying amounts of water vapour. It can vary from practically zero in the hot deserts to about 5% in the tropical forests.
Air over busy cities often contains toxic gases such as sulphur dioxide and carbon monoxide. Air over industrial areas may even contain traces of hydrogen and methane in addition to the other components of the air.
Microorganisms such as bacteria and viruses are also present in the air. Do you know that we often catch common cold because of the microorganisms in the air?
Why do we often detect the strong smell of disinfectants in hospitals?
Chlorofluorocarbons, dust, grit, smoke, and compounds of lead are some of the tiny solid particles that are contained in the air. These particles often pollute the air. What particle or particles in the air cause haze? Haze causes serious health problems. People with asthma have died from breathing in hazy air. What must we do to prevent the air from being hazy?
Ozone is a compound made up of three oxygen atoms chemically combined together. It forms a layer high up in the Earth’s atmosphere. This layer protects the Earth from the harmful ultraviolet rays of the Sun.
O3
Notes Air is a mixture of gases consisting of : • Nitrogen •Oxygen •Inert gases •Carbon dioxide •Dust, microogranisms and water vapour
78% 21% <1% 0.03%
Toxic gases, microorganisms, dust, smoke, grit, chlorofluorocarbons (CFCs), compounds of lead and ozone are also present in our air.
CHAPTER 5
The Air Around Us 5.2
Properties of Oxygen and Carbon Dioxide
List the properties of oxygen and carbon dioxide Identify oxygen and carbon dioxide based on their properties Choose suitable test for oxygen and carbon dioxide
Click on page as long as red bullet still exist
Properties of Oxygen is a colourless and odourless gas at room temperature. is soluble in water. is very active as it readily combines chemically with many substances to form new substances. supports combustion as burning will not occur without oxygen.
is needed for respiration by living things. is produced by green plants during photosynthesis.
Properties of Carbon Dioxide is a colourless and odourless gas at room temperature.
is slightly more soluble in water than oxygen. Does not burn nor support combustion.
Is needed by plant to make food during photosynthesis is produced when living things respire, when carbon or carbon compounds such as hydrocarbons and carbonates are burnt and when carbohydrates such as sugars and starch are fermented. Dissolves in water to form weak acids
Properties
Oxygen
Carbon dioxide
Solubility in water
Slightly soluble
Slightly soluble
Solubility in sodium hydroxide solution
Not soluble
Very soluble
Effect on glowing splinter
The splinter ignites Oxygen supports burning
The splinter goes out Carbon dioxide does not support burning
Effect on burning wooden splinter
The splinter burns brighter Oxygen supports burning
The splinter goes out Carbon dioxide does not supports burning
Effect on moist blue litmus paper or moist red litmus paper
Oxygen has no effect on blue litmus paper or red litmus paper Oxygen is a neutral gas
Blue litmus paper : Changes to red Red litmus paper : No Change of colour Carbon dioxide is an acidic gas
Effect on lime water
No change
Lime water turns cloudy
No change
Changes the colour of bicarbonate indicator from red to yellow
Effect on bicarbonate indicator
CHAPTER 5
The Air Around Us 5.3
Oxygen is needed in respiration
State that energy, CO2 and water vapor are the products of respiration Relate that living things use oxygen and give out , CO2 during respiration Compare and contrast the content of oxygen in inhaled and exhaled air in humans State that oxygen is needed for respiration Carry out experiment to show that living things use O2 and give out CO2 during respiration Click on page as long as red bullet still exist
Respiration
The process where our body obtains energy from food is called respiration.
Respiration takes place in our body Energy Oxygen
Food (Sugar)
Water Vapour
Carbon dioxide
Composition Of Inhaled & Exhaled AIr Breath In
Breath Out
Oxygen (O2)
Carbon Dioxide (CO2)
INHALE
EXHALE
Composition
Inhaled Air
Exhaled Air
Oxygen
High (21%)
Low (16%)
Carbon Dioxide
Low (0.03%)
High (4%)
Water Vapour
Less
More
Nitrogen
No changes
No changes
CHAPTER 5
The Air Around Us 5.4
Oxygen is needed for combustion State what combustion is State that oxygen is needed for combustion List the products of combustion Carry out experiments to investigate combustion
Click on page as long as red bullet still exist
Combustion ? Combustion is an oxidation reaction between a substance and oxygen to give out
oxide (or oxides) and energy. If the combustion is accompanied by flames, the process is called burning. Thus burning is a rapid combustion reaction between a substance and oxygen giving out
light and heat.
When carbon (an element) burns in oxygen, an oxide is formed. Charcoal, an example carbon, burns in excess dioxide oxygen to produce Carbon + ofoxygen →carbon carbon dioxide gas.
Condition for combustion ? The presence of OXYGEN The Presence of fuel
Enough amount of Heat is present
Combustion will not take place if any of these condition is not present
Combustion of carbon Carbon + oxygen
Combustion
Heat energy
+ Light energy
+ Carbon Dioxide
Combustion of hydrocarbon Hydrocarbon + oxygen
Combustion
Heat energy
+ Light energy
+ Carbon Dioxide
+ Water
CHAPTER 5
The Air Around Us 5.5
Air Pollution Explain what is air pollution List examples of air pollutants List the sources of air pollutants Describe the effects of air pollution Explain the steps needed to prevent and control air pollution
Click on page as long as red bullet still exist
We say that there is air pollution when there is a SUBSTANCE THAT ARE HARMFUL to our health and can cause damage to our environment are found in the air POLLUTANTS DUST CO2
SMOKE SULPHUR DIOXIDE
CARBON MONOXIDE
PESTICIDES
NITROGEN OXIDE
The sources of air pollutants include motor vehicles, factories, power plants, open burning and misuse of pesticides
Air Pollutants
Source of Pollutants
Gases (Carbon dioxide) and smoke Carbon monoxide, sulphur dioxide Haze
Motor vehicles and factories
Chlorofluorocarbon
Aerosol spray, electronics factories
Motor vehicles Open burning
EFFECTS OF AIR POLLUTION TO OUR HEALTH
Air Pollutant
Effect
Asbestos particles
Lung cancer
Gases from motor vehicles
Liver failure and cancer
Carbon monoxide
Headaches, brain damage or death Bronchitis, pneumonia, lung cancer
Sulphur dioxide
Acid rain: damages plants and make iron rust faster
Chlorofluorocarbon
Causes damage to the ozone layer. Too much exposure to UV rays can cause, skin cancer, eye diseases and the break-down of the body’s immune system
Carbon dioxide
Causes green house effect – Will result global warming, changes in climate, rising sea levels/ flooding
CHAPTER 5
The Air Around Us 5.6 The Importance of Keeping the Air Clean Describe how life would be without clean air Suggest ways to keep the air clean Practice habits that keep the air clean
Click on page as long as red bullet still exist
Steps to prevent air pollution Limit the use of CFC in industry Encourage the use of biodiesel in cars
Encourage the use of solar energy Relocate factories away from urban areas
Factories of chimneys are built to a certain height Avoid open burning
Minimise smoking habit
SMK Perempuan Likas Sabah
The Air Around Us 5.1
What is air made of State what is air made of Explain why air is mixture State the everage percentage of nitrogen, oxygen and carbon dioxide Carries out activities that shows: 1. The percentage of oxygen 2. That air contains water vapour, microorganisms and dust Click on page as long as red bullet still exist
All living things need air to live.We can fast for a day or two without taking any food or water, but how long can we live without air? Take a deep breath and hold it as long as you can. Then exhale onto your palm. Can you feel the air coming out from your nostrils? We cannot see the air but we know it is there. Earth is surrounded by 30 kilometres of air: a mixture of several different gases mixed together in different proportions. Unfortunately the air around us is becoming polluted by the day. Can we live in polluted air? What must we do to keep the air clean to save ourselves and the rest of the world?
What Is The Composition Of Air ? Air is a mixture of different gases. The pie chart shows the composition of air by percentage. What is the average percentage of nitrogen, oxygen, carbon dioxide and inert gases in the air? Why is the word ‘average’ used in the earlier question?
Oxygen 21% Nitrogen 78%
Carbon dioxide 0.03%
Inert gases <1%
Air as Mixtures As a mixture, the composition of air varies from place to place and time to time. Air also contains varying amounts of water vapour. It can vary from practically zero in the hot deserts to about 5% in the tropical forests.
Air over busy cities often contains toxic gases such as sulphur dioxide and carbon monoxide. Air over industrial areas may even contain traces of hydrogen and methane in addition to the other components of the air.
Microorganisms such as bacteria and viruses are also present in the air. Do you know that we often catch common cold because of the microorganisms in the air?
Why do we often detect the strong smell of disinfectants in hospitals?
Chlorofluorocarbons, dust, grit, smoke, and compounds of lead are some of the tiny solid particles that are contained in the air. These particles often pollute the air. What particle or particles in the air cause haze? Haze causes serious health problems. People with asthma have died from breathing in hazy air. What must we do to prevent the air from being hazy?
Ozone is a compound made up of three oxygen atoms chemically combined together. It forms a layer high up in the Earth’s atmosphere. This layer protects the Earth from the harmful ultraviolet rays of the Sun.
O3
Notes Air is a mixture of gases consisting of : • Nitrogen •Oxygen •Inert gases •Carbon dioxide •Dust, microogranisms and water vapour
78% 21% <1% 0.03%
Toxic gases, microorganisms, dust, smoke, grit, chlorofluorocarbons (CFCs), compounds of lead and ozone are also present in our air.
CHAPTER 5
The Air Around Us 5.2
Properties of Oxygen and Carbon Dioxide
List the properties of oxygen and carbon dioxide Identify oxygen and carbon dioxide based on their properties Choose suitable test for oxygen and carbon dioxide
Click on page as long as red bullet still exist
Properties of Oxygen is a colourless and odourless gas at room temperature. is soluble in water. is very active as it readily combines chemically with many substances to form new substances. supports combustion as burning will not occur without oxygen.
is needed for respiration by living things. is produced by green plants during photosynthesis.
Properties of Carbon Dioxide is a colourless and odourless gas at room temperature.
is slightly more soluble in water than oxygen. Does not burn nor support combustion.
Is needed by plant to make food during photosynthesis is produced when living things respire, when carbon or carbon compounds such as hydrocarbons and carbonates are burnt and when carbohydrates such as sugars and starch are fermented. Dissolves in water to form weak acids
Properties
Oxygen
Carbon dioxide
Solubility in water
Slightly soluble
Slightly soluble
Solubility in sodium hydroxide solution
Not soluble
Very soluble
Effect on glowing splinter
The splinter ignites Oxygen supports burning
The splinter goes out Carbon dioxide does not support burning
Effect on burning wooden splinter
The splinter burns brighter Oxygen supports burning
The splinter goes out Carbon dioxide does not supports burning
Effect on moist blue litmus paper or moist red litmus paper
Oxygen has no effect on blue litmus paper or red litmus paper Oxygen is a neutral gas
Blue litmus paper : Changes to red Red litmus paper : No Change of colour Carbon dioxide is an acidic gas
Effect on lime water
No change
Lime water turns cloudy
No change
Changes the colour of bicarbonate indicator from red to yellow
Effect on bicarbonate indicator
CHAPTER 5
The Air Around Us 5.3
Oxygen is needed in respiration
State that energy, CO2 and water vapor are the products of respiration Relate that living things use oxygen and give out , CO2 during respiration Compare and contrast the content of oxygen in inhaled and exhaled air in humans State that oxygen is needed for respiration Carry out experiment to show that living things use O2 and give out CO2 during respiration Click on page as long as red bullet still exist
Respiration
The process where our body obtains energy from food is called respiration.
Respiration takes place in our body Energy Oxygen
Food (Sugar)
Water Vapour
Carbon dioxide
Composition Of Inhaled & Exhaled AIr Breath In
Breath Out
Oxygen (O2)
Carbon Dioxide (CO2)
INHALE
EXHALE
Composition
Inhaled Air
Exhaled Air
Oxygen
High (21%)
Low (16%)
Carbon Dioxide
Low (0.03%)
High (4%)
Water Vapour
Less
More
Nitrogen
No changes
No changes
CHAPTER 5
The Air Around Us 5.4
Oxygen is needed for combustion State what combustion is State that oxygen is needed for combustion List the products of combustion Carry out experiments to investigate combustion
Click on page as long as red bullet still exist
Combustion ? Combustion is an oxidation reaction between a substance and oxygen to give out
oxide (or oxides) and energy. If the combustion is accompanied by flames, the process is called burning. Thus burning is a rapid combustion reaction between a substance and oxygen giving out
light and heat.
When carbon (an element) burns in oxygen, an oxide is formed. Charcoal, an example carbon, burns in excess dioxide oxygen to produce Carbon + ofoxygen →carbon carbon dioxide gas.
Condition for combustion ? The presence of OXYGEN The Presence of fuel
Enough amount of Heat is present
Combustion will not take place if any of these condition is not present
Combustion of carbon Carbon + oxygen
Combustion
Heat energy
+ Light energy
+ Carbon Dioxide
Combustion of hydrocarbon Hydrocarbon + oxygen
Combustion
Heat energy
+ Light energy
+ Carbon Dioxide
+ Water
CHAPTER 5
The Air Around Us 5.5
Air Pollution Explain what is air pollution List examples of air pollutants List the sources of air pollutants Describe the effects of air pollution Explain the steps needed to prevent and control air pollution
Click on page as long as red bullet still exist
We say that there is air pollution when there is a SUBSTANCE THAT ARE HARMFUL to our health and can cause damage to our environment are found in the air POLLUTANTS DUST CO2
SMOKE SULPHUR DIOXIDE
CARBON MONOXIDE
PESTICIDES
NITROGEN OXIDE
The sources of air pollutants include motor vehicles, factories, power plants, open burning and misuse of pesticides
Air Pollutants
Source of Pollutants
Gases (Carbon dioxide) and smoke Carbon monoxide, sulphur dioxide Haze
Motor vehicles and factories
Chlorofluorocarbon
Aerosol spray, electronics factories
Motor vehicles Open burning
EFFECTS OF AIR POLLUTION TO OUR HEALTH
Air Pollutant
Effect
Asbestos particles
Lung cancer
Gases from motor vehicles
Liver failure and cancer
Carbon monoxide
Headaches, brain damage or death Bronchitis, pneumonia, lung cancer
Sulphur dioxide
Acid rain: damages plants and make iron rust faster
Chlorofluorocarbon
Causes damage to the ozone layer. Too much exposure to UV rays can cause, skin cancer, eye diseases and the break-down of the body’s immune system
Carbon dioxide
Causes green house effect – Will result global warming, changes in climate, rising sea levels/ flooding
CHAPTER 5
The Air Around Us 5.6 The Importance of Keeping the Air Clean Describe how life would be without clean air Suggest ways to keep the air clean Practice habits that keep the air clean
Click on page as long as red bullet still exist
Steps to prevent air pollution Limit the use of CFC in industry Encourage the use of biodiesel in cars
Encourage the use of solar energy Relocate factories away from urban areas
Factories of chimneys are built to a certain height Avoid open burning
Minimise smoking habit
SMK Perempuan Likas Sabah
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