Science and Materials in Nature

In this section, you will learn that air is made up of different gases. You will discover the main gases found in air and understand how they are useful in nature and in our daily lives.

Through simple experiments, you will learn how to prepare carbon dioxide and oxygen in the lab, explore their properties, and identify their uses.

By the end of the lesson, you should be able to describe what air is made of, explain the role of each gas, and demonstrate how to make carbon dioxide and oxygen, as well as explain their uses.

KEY IDEAS

• Air is a mixture of gases: Air is made up of many gases, not just one. These include nitrogen, oxygen, carbon dioxide, and others.

• Carbon dioxide helps plants make food: Plants use carbon dioxide to make their food through photosynthesis.

• Nitrogen is the most common gas in air: Nitrogen makes up most of the air and is used to help plants grow.

• Oxygen is needed for breathing and burning: We need oxygen to stay alive, and it also helps things burn.

• Small gases have big uses: Gases like helium and ozone are found in tiny amounts but are useful in lights, medicine, and protecting the Earth.

Meaning of Air

Air is an invisible mixture of gases (mainly of oxygen and nitrogen that cover the earth, each present in different proportions. These gases work together to:

1. Support life on Earth

2. Influence weather patterns

3. Enable industrial processes.

Properties of Air

₁. Air has mass: Even though we cannot see it, air is made up of particles and therefore has mass. This can be shown by weighing a deflated balloon and then weighing it again when filled with air; the balloon becomes heavier.

2. Air occupies space: Air takes up space, even though it is invisible. For example, when you blow air into a balloon, it expands because air fills it.

3. Air is compressible: Air can be squeezed into a smaller space. This is why pumps can force more air into tyres or balls.

4. Air exerts pressure: The particles in air constantly move and collide with surfaces, creating air pressure. This is why inflated tyres or football stay firm.

5. Air supports burning: Oxygen in air helps things burn. A fire will go out if there is no air or not enough oxygen.

Figure 1.1: Properties of air Rather than being a single pure substance, air is made up of various gases in specific proportions. These are nitrogen, oxygen, carbon dioxide, argon, water vapour and trace gases such as neon and helium. Each of these components plays a vital role in environmental processes and human activities.

Understanding air as a mixture helps us appreciate how these gases interact to support breathing, combustion, plant growth, industrial processes, and climate regulation.

Composition of Air

Table 1.1: Components of clean dry air and their percentage composition Component of air Volume by % Symbol of the gaseous element Nitrogen 78.08 N2 Oxygen 20.95 O2 Argon 0.93 Ar Carbon Dioxide 0.040 CO2 Other gases (trace gases) Neon 0.0018 Ne Helium 0.0005 He Krypton 0.0001 Kr Hydrogen 0.00005 H2 Xenon 8.7 x 10 -6 Xe

1. Nitrogen Gas

Nitrogen gas is a colourless, odourless, and tasteless substance that makes up about 78% of the air we breathe. It exists as two atoms chemically joined together (N2) and does not support burning or breathing. Nitrogen is very important for living things because it helps in the formation of proteins in plants and animals. In industry, it is used to make fertilisers, explosives, and ammonia, and it is also used to preserve packaged foods by preventing spoilage.

Uses of Nitrogen gas Nitrogen plays a crucial role in various natural and industrial processes. Here are some of its main uses:

a. Agriculture (Fertilisers): Nitrogen is a key component of fertilisers such as urea and ammonium nitrate. Plants need nitrogen for growth as it helps in the formation of proteins and chlorophyll.

b. Biological importance: Nitrogen is found in all living organisms as part of amino acids, proteins, enzymes, and deoxyribonucleic acid (DNA). It is essential for cell development and reproduction.

c. Food industry: Nitrogen gas (which is inert, meaning it does not react with food components or change their flavour, aroma, or texture) is used to preserve packaged foods by displacing oxygen (which is the main cause of food spoilage through oxidation and the growth of aerobic bacteria) to prevent spoilage and bacterial growth.

d. Industrial applications:

i. Used to create an inert atmosphere in chemical processes and electronics manufacturing to prevent oxidation

ii. Used in the production of ammonia (NH3) through the Haber process, which is the foundation of many nitrogen-based products.

e. Medical uses: Liquid nitrogen (which has the ability to instantly freeze) is used for cryosurgery, which involves freezing and removing abnormal or diseased tissues, such as warts or precancerous cells.

f. Inflating aircraft and car tyres: Nitrogen is preferred in tyres because it is less likely to cause pressure changes due to temperature fluctuations and reduces oxidation inside the tyre.

2. Oxygen gas (O2) Oxygen is one of the most vital chemical elements in the air, represented by the symbol ‘O’ and atomic number 8. It is a highly reactive and combustible gas that forms compounds called oxides with other elements. Oxygen ranks third in abundance by mass in the universe, after hydrogen and helium. At standard temperature (273.15K) and pressure (1 atm), two atoms of oxygen form a molecule called dioxygen (O2), essential for respiration in living organisms.

Uses of oxygen ₐ. Respiration: Oxygen is essential for aerobic respiration in humans and animals.

It is the gas we breathe in to help break down food and release energy in cells.

Without oxygen, most living organisms cannot survive, as it plays a key role in cellular energy production.

b. Medical applications: Oxygen is widely used in hospitals and healthcare settings:

i. Oxygen therapy is provided to patients with breathing difficulties or respiratory conditions like asthma, pneumonia, and COVID-19.

ii. It is also used in anaesthesia machines during surgeries.

iii. Ambulances and emergency services carry oxygen cylinders for immediate first aid.

Figure 1.2: A patient on oxygen support

c. Industrial Processes: Oxygen is used in a range of industrial applications:

i. Steel manufacturing: Oxygen is blown into molten iron to remove impurities like carbon, producing high-quality steel.

ii. Chemical production: It is used in making chemicals such as nitric acid and hydrogen peroxide.

iii. Welding and cutting: Oxygen is used in combination with gases like acetylene in oxy-acetylene torches for welding, cutting, and brazing metals.

d. Aviation and space exploration: In high-altitude aviation and space missions, oxygen is supplied in tanks to pilots and astronauts since the atmospheric oxygen is too low or absent at those altitudes. It ensures proper breathing and life support.

e. Water treatment: Oxygen is used in wastewater treatment plants to help break down pollutants by supporting the growth of aerobic bacteria. It improves the efficiency of the biological treatment process.

f. Scuba diving: Scuba divers carry compressed oxygen tanks to breathe underwater.

Figure 1.3: Scuba diver with compressed oxygen tank under water

g. Environmental and laboratory uses

i. In environmental studies, oxygen sensors measure water quality by checking dissolved oxygen levels.

ii. It supports aquatic life, such as fish and other aquatic organisms depends on it as an essential component.

3. Carbon Dioxide Gas (CO2)

Carbon dioxide is represented by the chemical symbol ‘CO2’. Carbon dioxide is released during respiration and the decomposition of organic matter. It also occurs naturally from sources such as volcanoes, geysers, and hot springs. Additionally, the burning of fossil fuels like petroleum and natural gas produces significant amounts of carbon dioxide.

Uses of Carbon dioxide ₐ. Photosynthesis: Carbon dioxide plays a crucial role in the survival of plants through the process of photosynthesis. During this process, plants absorb carbon dioxide from the atmosphere and use it, along with sunlight and water, to produce glucose (a form of sugar) and oxygen. This is not only essential for plant growth but also vital for maintaining the oxygen balance in the atmosphere.

b. Food and beverage industry:

i. Carbonation: CO2 is widely used to carbonate beverages such as soft drinks, soda water, and sparkling wine, giving them their fizzy properties.

c. Preservation: In packaged foods, carbon dioxide is used to keep food fresh, preventing spoilage. It preserves food by inhibiting the growth of microorganisms and slowing down the natural degradation of food. Unlike nitrogen, which is mostly used to displace oxygen, CO2 has specific antimicrobial properties that actively interfere with bacterial survival. Fire extinguishers: Carbon dioxide is commonly used in fire extinguishers, especially for electrical fires and flammable liquids. It works by displacing oxygen around the fire and forming a blanket over the flames, thus cutting off the oxygen supply required for combustion.

d. Refrigeration (dry ice): In its solid form, carbon dioxide is known as dry ice. It is used as a cooling agent for the preservation of perishable goods such as meat, seafood, and medical supplies during storage and transport. Dry ice sublimes directly (into gas without passing through a liquid phase), making it very convenient for refrigeration without any mess.

e. Welding and industrial use: In industries, carbon dioxide is used as a shielding gas in gas metal arc welding (GMAW). It protects the welded area from atmospheric gases such as oxygen and nitrogen that could cause defects in the welded work.

CO2 is also used in the production of certain chemicals and plastics.

f. Greenhouses: A greenhouse is a structure designed to create a controlled, warmer environment for growing plants. It works by trapping solar radiation, preventing heat loss through convection and conduction. Carbon dioxide enrichment in greenhouses is a common practice used to promote faster and healthier plant growth. By increasing the concentration of CO2 in the air within a greenhouse, plants can photosynthesise more efficiently, resulting in better yields.

g. Fertiliser production

i. CO2 is an important raw material in the manufacture of urea, a nitrogen- based fertiliser used globally in agriculture.

ii. Urea (NH2CONH2) is formed when carbon dioxide reacts with ammonia under specific conditions. This fertiliser helps to increase crop yield and is vital for food production.

CO2 + 2 NH3 → NH2CONH2 + H2O

4. Water Vapour

Its amount varies depending on location and weather. It plays a vital role in cloud formation, rainfall, and temperature regulation through the greenhouse effect. Water vapour content in the air varies from 0.01% to 4.24%, depending on temperature. It is released during respiration and produced in many chemical reactions.

As an important gas in the atmosphere, it helps keep the Earth warm by regulating temperature (trapping heat); water vapour is a natural greenhouse gas. It absorbs and releases heat in the atmosphere, keeping our planet warm.

This is important for us for the following reasons

a. Supporting life: This helps maintain a temperature that is just right for plants, animals and humans to thrive.

b. Makes Earth a comfortable home: Helps in weather formation (Water Cycle):

Water vapour is a factor in weather systems. It contributes to cloud formation, storms, and rainfall.

i. In the water cycle, it helps form clouds; water vapour turns into clouds, makes rain and snow.

ii. Helps regulate temperature; Water vapour keeps Earth’s temperature stable.

5. Trace gases Trace gases are gases that are present in small amounts in the air.

Even though they are present in tiny amounts, these gases can be very important for

a. Technology: making neon signs and helium balloons.

b. Environment: Some trace gases can affect the climate.

c. Industry: They are used in various products and processes.

Even though trace gases make up less than 1% of the atmosphere, they can have a big impact.

Table 1.2: Uses of trace gases Gas Use Argon In bulbs, electronics and eye surgery.

Neon Glows in advertising signs.

Helium Fills balloons, cools MRI machines.

Methane Fuel for cooking and electricity.

Krypton In bright lights and insulated windows.

Hydrogen As rocket fuel, in green energy.

Ozone/Oxone Protects us from harmful sun rays and purifies water and air.

Perform the activity below in a group of four members, record and discuss your observations as a group.

Activity 1.1 Demonstrating effects of air on substances What you need

• A shallow dish or plate

• Water

• Food colouring (optional, for better visibility)

• A candle

• A lighter or matches

• A clear, wide-mouthed glass or jar What to do

1. Pour water into the dish and add food colouring if desired.

2. Place the candle in the centre of the dish and light it.

3. Carefully place the glass or jar over the burning candle, ensuring the bottom edge of the glass is submerged in the water.

4. Watch what happens to the candle and the water level as the candle burns.

5. Read and record your observation.

See Annex 1.0 on page xxxx for expected observations for activities.

Key questions

1. Which gas’s presence is indicated by the ability of the candle to burn?

2. What happens to the candle after burning for some time?

3. What happens to the level of water inside the glass?

4. Explain your observations in 1 and 2 above.

Safety precautions

1. Do not use plastic containers, as they can easily deform due to the changes in temperature of the air.

2. Move any inflammable substance away before lighting the candle.

Activity 1.2 Simulation of the behaviour of air Aim: Verify that Air Occupies Space What you need

• Empty glass

• Bowl of water What to do

1. Invert the glass and push it straight down into the water.

2. Record your observations and explain why they suggest that air occupies space.

Activity 1.3 Video to reinforce understanding of properties of air Click on the video link below to reinforce your understanding of the properties of air https://youtu.be/I3JtnoCnQ7w?si=078fND0fchPc0M7N

Activity 1.4 The components of air What to do

1. Develop a data table or model which represents the components of air (see Annex 1.0 for solutions).

2. Evaluate the roles of each of the components of air in sustaining life.

3. Consider how a change in air composition could impact the environment.

4. Explain why air is described as a mixture rather than a compound.

Activity 1.5 Research project Objective: To explore the composition of air and understand its roles in supporting life and natural processes.

Instructions

1. Introduction

a. Define what air is.

b. Briefly describe why studying air is important.

2. Components of Air

a. Identify the major gases in air (nitrogen, oxygen, carbon dioxide, etc.).

b. Include minor components like water vapour and noble gases.

c. Explain how these components vary in different environments (e.g., polluted cities vs. forests).

3. Uses of Air in Nature

a. Discuss how plants use air (photosynthesis and respiration).

b. Explain how animals and humans rely on oxygen for survival.

c. Describe natural processes such as wind, pollination, and weather cycles.

d. Mention the role of air in supporting fire and energy cycles.

4. Environmental Importance

a. Explore how clean air is essential for ecosystems.

b. Briefly touch on the effects of air pollution on nature.

5. Conclusion

a. Summarise the importance of air’s components and uses.

b. Reflect on why protecting air quality matters for the future.

6. Presentation

a. Present findings as a poster with diagrams.

b. Include at least 2 visuals (e.g., a pie chart of air composition, a diagram of photosynthesis).

c. Cite at least 3 reliable sources.

Dear learners, you are welcome to another exciting aspect of our studies. In our previous lesson, we studied the components of air, a mixture which includes oxygen and carbon dioxide. We saw their respective percentage compositions and various uses to which they are put. However, do these gases only exist naturally, or can they also be prepared? This week, we are going to learn about how carbon dioxide and oxygen can be prepared, in the laboratory, by way of chemical reactions. We shall also learn about their physical and chemical properties, as well as the various uses to which they can be put in everyday life

activities. You will look at the following areas:

a. Physical and chemical properties of carbon dioxide and oxygen.

b. Preparation of carbon dioxide and oxygen gases using available materials.

c. Test for carbon dioxide and oxygen.

Carbon dioxide (CO2) and oxygen (O2) are vital gases which are used in a variety of everyday

activities across various disciplines such as science, industry, agriculture, medicine and preservation of the natural environment.

CO2 is absorbed by plants and plankton during photosynthesis, which releases oxygen.

Humans and animals, in turn, inhale oxygen and exhale CO2, which is also released through decomposition and combustion. While oxygen is necessary for respiration and combustion, CO2 is a greenhouse gas that absorbs and re-radiates heat, trapping it in the atmosphere.

Human activities have disrupted the natural balance of this cycle, leading to increased atmospheric CO2 levels.

Carbon dioxide is also used in the production of carbonated beverages, fire extinguishers and serves as a crucial reactant in various chemical processes.

Oxygen is also widely used in industrial processes such as steelmaking, welding, and medical applications.

Laboratory preparation of carbon dioxide and oxygen gases In this lesson, we are going to use various methods to prepare both carbon dioxide and oxygen in the laboratory. We shall study the principles of the reactions involved, the necessary materials and apparatus used, step-by-step approaches, critical safety precautions, and the scientific reasons for choosing specific materials and methods.

Laboratory Preparation of Carbon Dioxide (CO2)

Carbon dioxide gas is commonly prepared in a laboratory by reacting an acid (usually dilute) with a carbonate or hydrogen carbonate of a metal. An example of such a reaction is the action of dilute hydrochloric acid on calcium carbonate (marble chips) in a test tube or conical flask.

The reaction produces calcium chloride, water, and carbon dioxide gas, which can then be collected by upward displacement of air because it is denser than air.

The balanced chemical equation for this reaction is:

CaCO3(s) + 2HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g) In the reaction, one mole of solid calcium carbonate reacts with two moles of aqueous hydrochloric acid to produce one mole of aqueous calcium chloride, one mole of liquid water, and one mole of gaseous carbon dioxide. The precise molar ratios are necessary for determining the needed amounts of reactants so as to help predict the theoretical yield of the product.

The reaction does not need external heating or additional energy input since it proceeds spontaneously at room temperature. This makes the method a practical choice for laboratory use.

Diagram: The chemicals and other equipment used are shown in the setup below.

Figure 1.4: Setup for preparation of carbon dioxide gas.

This type of reaction is classified as an acid-carbonate reaction, and it proceeds spontaneously at room temperature. The fact that the reaction occurs readily without external heating simplifies the experimental setup and reduces the need for additional energy input, making it a practical choice for laboratory use.

Key question What other methods can you use to prepare carbon dioxide gas?

Now, in a group of five people, prepare carbon dioxide gas using the materials provided and the procedures listed below. Do this activity under the supervision of an adult.

Activity 1.6 Preparing and testing carbon dioxide gas Aim: To prepare CO2 and use it to put out a fire.

What you need

• Baking soda (sodium bicarbonate) - 2 tablespoons

• White vinegar /lemon/lime juice - 100ml

• Large plastic bottle (500ml or 1 litre)

• Balloon

• Funnel (or rolled paper)

• Drinking straw

• Candle and lighter/match

• Spatula and beaker What to do

Step 1: Set up

a. Pour the vinegar into the plastic bottle (about 1/3 full).

b. Using the funnel, carefully add baking soda to the balloon.

c. Stretch the balloon’s opening over the bottle neck without letting baking soda fall into the bottle yet.

Step 2: Gas production

a. Lift the balloon to let all the baking soda fall into the vinegar.

b. Watch the immediate fizzing reaction.

c. The balloon will inflate as CO2 gas is produced.

d. Wait 2-3 minutes for maximum gas production.

Step 3: Collecting the gas

a. Carefully remove the balloon from the bottle.

b. Twist the balloon’s neck to keep gas inside.

c. Record your observation

Step 4: Testing

a. Light the small candle.

b. Carefully release the invisible CO2 gas from the balloon into the candle flame

c. Write down your observation in your notebook.

Chemical Reaction

Baking soda + Vinegar → Salt + Water + Carbon dioxide NaHCO3 + CH3COOH → CH3COONa + H2O + CO2 Safety precautions ₁. Avoid spillage of chemicals.

2. Wash any chemical that gets in contact with your body immediately with a lot of water.

3. Do not ingest (do not taste or drink) the vinegar.

4. Do not put the lighter near any combustible substance.

Key question What shows that a gas was produced? Write down the answer to this question in your notebook.

Activity 1.7 Test for carbon dioxide (CO₂) in exhaled air Aim: To show CO2 is present in exhaled air.

What you need

• Delivery tube

• Lime water

• Rubber cork

• Test tube containing CO2 What to do

1. Prepare lime water by dissolving about 5g of calcium hydroxide [Ca (OH)2] in water.

2. Bubble the CO2 gas through the limewater out of your mouth. You can use a straw, tubing, or a delivery tube to gently pass the gas through the limewater.

3. Look carefully and write down your observation of the reaction.

Chemical equation of the reaction CO2 (g) + Ca(OH)2 (aq) → CaCO3 (s) + H2O (l) This is a standard and reliable test for detecting carbon dioxide gas.

Safety precautions ₁. Use clean apparatus: Ensure the delivery tube and beaker are washed before and after the experiment to avoid contamination.

2. Do not share mouthpieces: Each student should have their own straw or tube to prevent spreading germs.

3. Avoid swallowing limewater: Limewater (calcium hydroxide solution) is mildly caustic; do not drink it.

4. Rinse immediately if spilt: If limewater comes into contact with skin or eyes, wash thoroughly with clean water.

5. Use small amounts: Only a small quantity of limewater is needed to reduce risk.

6. Dispose safely: Pour used limewater into a designated waste container, not down sinks without teacher permission.

7. Work under supervision: Always experiment with a teacher or lab supervisor present.

Figure 1.5: Testing for carbon dioxide.

Real-world application Atmospheric carbon dioxide plays a crucial role in the formation of calcium carbonate rocks like limestone. It dissolves in water, forming carbonic acid, which then reacts with rocks, dissolving calcium and other ions. These ions are transported to the ocean and, along with marine organisms, contribute to the precipitation of calcium carbonate, which, over time, forms sedimentary rock.

Other processes which produce CO2 gas ₁. Combustion: Burning of fossil fuels (coal, oil, natural gas), organic materials (wood, paper, etc.).

2. Respiration: Both aerobic and anaerobic respiration in living organisms.

During cellular respiration, glucose reacts with oxygen to produce carbon dioxide, water, and energy. Decomposition of organic matter by bacteria also releases carbon dioxide.

3. Fermentation: In brewing and bread making, fermentation processes produce carbon dioxide.

Key question Describe the process of bread making, explaining the scientific principles involved, which led to the formation and release of carbon dioxide gas.

Table 1.3: Comparison of laboratory preparation methods for carbon dioxide Method Reactants Products (excluding CO2) Conditions Advantages Disadvantages Reaction of calcium carbonate (CaCO3) with HCl CaCO3, HCl CaCl2, H2O Room temperature Readily available reactants, relatively Requires an airtight apparatus Reaction of baking soda with vinegar NaHCO3, CH3COOH CH3COONa, H2O Room temperature Simple and safe, readily available at home May produce CO2 mixed with air Thermal decomposition of CaCO3 CaCO3 CaO High temperature Produces, relatively, pure CO2 if done correctly Requires high temperature, is energy-intensive Laboratory Preparation of Oxygen (O2) gas Oxygen gas can be prepared in the laboratory by a number of methods as follows:

1. Electrolysis of water.

2. Catalytic decomposition of hydrogen peroxide.

3. Heating metal oxides or oxo-compounds such as potassium chlorate

4. Photosynthesis of pond weed.

All of the methods above are preferred laboratory choices due to the availability of the chemicals and other materials involved.

Catalytic Decomposition of Hydrogen Peroxide

This method is most preferred due to its relative convenience and safety. Also, its reaction does not require high temperatures to take place.

In this reaction, hydrogen peroxide breaks down into water and oxygen gas in the presence of manganese (IV) oxide (MnO2) as a catalyst.

The balanced chemical equation for this reaction is: 2H2O2(aq) → 2H2O(l) + O2(g) In the equation, two moles of aqueous hydrogen peroxide decompose to yield two moles of liquid water and one mole of gaseous oxygen.

MnO2, as a catalyst, accelerates the rate of the decomposition of hydrogen peroxide without itself undergoing any permanent chemical change. The catalyst can be recovered chemically unchanged at the end of the reaction.

Now, let us prepare and test for oxygen gas.

Perform this activity in a group of four members.

Activity 1.8a Preparation and testing of oxygen gas Aim: To prepare and test for oxygen gas What you need

• 3% hydrogen peroxide (from pharmacy/first aid kit) - 100ml

• Fresh raw potato - 1 medium piece

• Large clear plastic bottle (500ml)

• Small balloon or plastic bag

• Knife

• Funnel or spoon What to do

1. Cut the potato into small cubes (about 1cm pieces).

2. Pour hydrogen peroxide into the plastic bottle.

3. Drop potato pieces into the hydrogen peroxide.

4. Immediate fizzing and bubbling begin.

5. Quickly stretch a balloon over the bottle opening to collect the oxygen gas.

6. Fasten the mouth of the balloon to keep the oxygen gas in it.

7. Record your observation.

Chemical Reaction

Hydrogen peroxide → water + oxygen gas 2H2O2 → 2H2O + O2 (catalysed by potato enzyme, which is readily available instead of manganese (IV) oxide).

Expected safety precautions ₁. Always wear safety goggles to protect the eyes.

2. Handle hydrogen peroxide with care as it can cause skin irritation and burns.

3. Use the knife carefully while cutting the potato

4. Do not direct the glowing splint to yourself or anyone before rekindling Troubleshooting ₁. If no bubbles form

a. Check if the hydrogen peroxide is fresh (old peroxide loses effectiveness).

b. Ensure potato is fresh and not cooked.

c. Use more catalyst (potato pieces).

d. Warm the reaction mixture to a higher temperature.

2. If the reaction is too vigorous

a. Use less catalyst.

b. Add catalyst slowly.

c. Use cooler hydrogen peroxide.

d. Work with smaller quantities of reactants.

Activity 1.8b Alternative preparation of oxygen using an aquatic plant What you need

• Aquatic plants (pond weed, elodea, or any underwater plant)

• Clear container or glass bowl

• Water (preferably pond or aquarium water)

• Bright sunlight or strong lamp

• Inverted funnel or large plastic bottle with the bottom cut off

• Test tube or small jar for gas collection What to do

1. Fill the container with water.

2. Place aquatic plants in water.

3. Invert the funnel over plants and place the test tube over the funnel spout.

4. Place in bright sunlight or under a strong lamp.

5. The time needed for the result to be observed clearly is 2-4 hours.

Expected Observation

Bubbles of a gas (oxygen) rise and collect in a test tube.

Chemical Equation

This is a biological process which produces oxygen by photosynthesis.

The chemical equation of the process is 6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

Activity 1.9 Test for oxygen gas Aim: To show that oxygen supports combustion.

What you need

• Wooden splint, toothpick, or thin wooden stick

• Lighter

• Container with suspected oxygen gas

• Safety supervision What to do

1. Light a wooden splint and let it burn for a few seconds.

2. Blow out the flame, leaving the wood glowing red-hot at the tip.

3. Quickly insert the glowing splint into the gas sample.

4. Record your observations.

Key question: What safety precautions did you observe during the activity to avoid waste, injury and damage? In your groups, write them down and discuss them. Share your thoughts with other groups.

Safety Precautions

1. Always wear safety goggles to protect the eyes.

2. Handle hydrogen peroxide with care as it can cause skin irritation and burns, especially at higher concentrations. Avoid contact with skin and eyes, and in case of contact, wash the affected area immediately with plenty of water.

3. Ensure that the apparatus is set up on a stable surface to prevent any accidental spills or breakage.

4. Avoid contact between manganese (IV) oxide and organic materials, as it is a strong oxidising agent and can cause vigorous reactions.

Activity 1.10 Compare and contrast: Physical and Chemical Characteristics of Carbon Dioxide and Oxygen Gases Procedure

1. Physical Characteristics

a. Research (or note from your experiments) the colour, odour, and state of each gas.

b. Record similarities and differences.

2. Chemical Characteristics: Test effect on a burning candle: oxygen supports burning, carbon dioxide extinguishes flame.

3. Discussion Questions

a. How are oxygen and carbon dioxide alike in appearance?

b. What key chemical tests can distinguish between the two?

c. Why are these differences important for living things and the environment?

Activity 1.11 Research task: Uses of Oxygen and Carbon Dioxide in Domestic and Industrial Settings and a Role Play of Professionals Using Oxygen and Carbon Dioxide in their Work Objective: To investigate how oxygen (O2) and carbon dioxide (CO2) are used in domestic and industrial settings.

Part 1: Research uses of oxygen and carbon dioxide.

Instructions

1. Work in small groups of 4-6 people.

2. Assign one use of carbon dioxide or oxygen to each person to research.

Examples:

a. Oxygen

i. Domestic uses (e.g., medical breathing support, fish tanks, home welding).

ii. Industrial uses (e.g., steel production, cutting and welding metals, rocket fuels).

b. Carbon Dioxide

i. Domestic uses (e.g., carbonated drinks, fire extinguishers, dry ice for cooling).

ii. Industrial uses (e.g., refrigeration, food preservation, chemical manufacturing, agriculture in greenhouses).

3. Present your research verbally to the other members of your group.

Part 2: Role Play Activity

Objective: To demonstrate how professionals use oxygen and carbon dioxide in real- life work situations.

Instructions

1. Form small groups (3–5 students).

2. Choose one profession involving oxygen or carbon dioxide, such as:

a. Doctor/Paramedic – giving oxygen to a patient.

b. Welder – using oxygen in metal cutting.

c. Food Industry Worker – using CO2 in soda production.

d. Firefighter – using a CO2 fire extinguisher.

e. Greenhouse Farmer – using CO2 to enhance plant growth.

3. Write a short script (3–5 minutes) showing how the gas is used in the job.

4. Perform the role play for the class.

5. After the role play, briefly explain the science behind the use of the gas in that profession.

1. What are the main components, and the relative amounts of these, in air?

2. How does an increase in carbon dioxide levels, reduced oxygen levels, and increased air pollution affect living organisms?

3. A chemistry teacher wants to demonstrate gas preparation to students but has limited laboratory equipment. The school only has access to household materials like baking soda, vinegar, hydrogen peroxide, fresh potatoes, and basic glassware.

a. Analyse and evaluate the best approach for preparing both carbon dioxide and oxygen gases.

b. Design a setup for collecting both gases that maximises safety and efficiency.

Oil and natural gas are important sources of energy. They were formed millions of years ago from the remains of plants and animals buried deep under the ground. Over time, heat and pressure turned these remains into fossil fuels.

In this section, you will learn that natural gas is mostly made of methane, while crude oil contains many different substances called hydrocarbons, including alkanes. You will also find out how oil and gas are formed, taken from the ground, and used in daily life; for

example, for fuel, cooking, electricity, making plastics, and fertilisers.

KEY IDEAS

• Benefits of crude oil and natural gas.

• Composition of crude oil.

• Difference in composition of crude oil and natural gas.

• Environmental impacts of crude oil and natural gas.

• Extraction of the components of crude oil.

Dear learner, you are welcome to yet another exciting week. Guess what? Let’s call this week a week of “black gold.” Make no mistake, gold cannot be black. This is only a jargon which refers to crude oil and natural gas. You may have heard of rich countries associated with petroleum and natural gas. What is their success story, and why do crude oil and natural gas enrich them? Let us find out about “black gold.”

Crude Oil Composition

Crude oil is a naturally occurring, unrefined liquid petroleum, a mixture of hydrocarbons (compounds made mainly of hydrogen and carbon) that is found accumulated underground in the earth’s crust. Various types of crude oils with different properties are available in the market. Its price depends upon density as well as the presence of sulphur, metals, and other contaminants present in it. The composition of crude oil varies with the geographical location, age, and depth of the well.

The composition of crude oil can be categorised based on the presence of elements, molecules, and compounds present in it. Basically, crude oil is composed of;

1. Hydrocarbon compounds

2. Non-hydrocarbon compounds

3. Inorganic substances.

Figure 2.1: Crude oil Hydrocarbons These include alkanes (paraffins), cycloalkanes, aromatic hydrocarbons (arenes) and asphaltenes.

1. Alkanes (Paraffins): Alkanes, also called paraffins, are saturated hydrocarbons which contain only single bonds between carbon atoms. They have the general chemical formula, CnH2n+2. They can form straight-chain compounds (normal alkanes) or branched-chain ones (iso-alkanes).

Examples of alkanes include methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10). Heavier alkanes are found in substances like gasoline, kerosene, and lubricating oils. Of all hydrocarbons, paraffins are usually the most abundant in crude oil.

2. Cycloalkanes (Naphthenes or Cycloparaffins): Cycloalkanes are also known as naphthene. They are saturated hydrocarbons which have ring structures. Their general formula is CnH2n. Examples include cyclopentane and cyclohexane. These compounds are important parts of gasoline and other products from petroleum refineries. Like alkanes, they are also saturated, but their ring structure gives them different chemical properties.

cyclohexane cyclopentane

3. Aromatic Hydrocarbons (Arenes): Aromatic hydrocarbons, or arenes, contain one or more benzene rings. A benzene ring is a structure made of six carbon atoms with alternating double bonds. The simplest example is benzene (C6H6). Others are toluene, xylene, and more complex compounds known as polycyclic aromatic hydrocarbons (PAHs). Aromatic compounds are valued for their role in increasing gasoline’s octane rating. They are also used as starting materials in the chemical industry.

benzene 1,4-dimethylbenzene (para-xylene

4. Asphaltenes: These are large and complex hydrocarbon molecules. They often contain atoms such as nitrogen, sulphur, and oxygen, along with small amounts of metals like vanadium and nickel. Unlike lighter hydrocarbons, asphaltenes are insoluble in low- boiling liquids like propane or butane, but soluble in carbon disulphide. They increase the density and thickness (viscosity) of crude oil and are common in bitumen and heavy oils.

Non-Hydrocarbon Compounds

Crude oil also contains organic compounds that are composed of elements other than carbon and hydrogen. They include sulphur compounds, nitrogen compounds, oxygen compounds and organometallic compounds.

These are heteroatoms which can significantly impact the properties and refining processes of crude oil.

1. Sulphur compounds: They range from simple hydrogen sulphide (H2S) to more complex organic sulphur compounds such as mercaptans (thiols), sulphides, disulfides, and thiophenes. Sulphur content is a key factor in crude oil quality. “Sweet crude” has low sulphur content, while “sour crude” has high sulphur content. High sulphur content can lead to corrosion and environmental issues during refining and combustion processes of crude oil.

2. Nitrogen compounds: These are basic or neutral organic compounds which contain nitrogen atoms within their molecular structures. Examples are pyridines, quinolines and porphyrins. Nitrogen compounds can poison catalysts used in refining processes.

3. Oxygen compounds: These include organic acids (naphthenic acids), phenols, ketones, ethers, and esters. Presence of organic acids in crude oil can contribute to corrosion.

4. Organometallic compounds: These contain metal atoms (like nickel and vanadium) chemically bonded to organic molecules, often associated with porphyrin structures.

They can cause catalyst deactivation during refining and contribute to deposits.

Inorganic components Crude oil also contains trace amounts of dissolved inorganic salts (e.g., chlorides of sodium, calcium, and magnesium) and water. These need to be removed during processing to prevent corrosion and damage of equipment.

Natural Gas

Natural gas is a naturally occurring gaseous hydrocarbon mixture which consists primarily of lighter alkanes. Its composition is generally simpler than that of crude oil. it is an important source of energy used in many parts of our daily lives.

Natural gas is cleaner than other fossil fuels like coal and oil, and it plays a big role in Ghana’s electricity supply, cooking, industry, and transport.

Composition of Natural Gas (by Volume)

₁. Methane (CH4): Is the dominant component, ranging from 70% to 99%.

2. Ethane (C2H6): Is usually present in smaller amounts than methane.

3. Propane (C3H8) and Butane (C4H10): These are often present in varying, but generally lower, concentrations. When natural gas is rich in propane and butane, it is sometimes referred to as “wet gas.”

4. Pentanes (C5H12) and heavier hydrocarbons: These may be present in trace amounts.

It may condense out as natural gas liquids (NGLs) under certain conditions.

Non-hydrocarbon gases Natural gas often contains varying amounts of other gases which are not hydrocarbons.

These are:

1. Carbon dioxide (CO2): It can range from trace amounts to significant percentages.

It needs to be removed as it reduces the heating value of natural gas and can cause corrosion.

2. Nitrogen (N2): Is another common non-hydrocarbon component that dilutes natural gas and reduces its heating value.

3. Hydrogen sulphide (H2S): Is a toxic and corrosive gas that must be removed. Its presence makes the gas “sour” or unusable. To make it usable, the “sour” gas undergoes a “gas sweetening” process to remove H2S and CO2, producing “sweet gas.”

4. Water vapor (H2O): Needs to be removed to prevent corrosion and hydrate formation in pipelines.

5. Helium (He): In some specific locations, natural gas can contain commercially viable amounts of helium.

6. Other trace gases like argon (Ar).

Differences Between Natural Gas And Crude Oil In Com- position ₁. State at surface conditions: Crude oil is liquid at standard temperature and pressure, while natural gas is gaseous.

2. Molecular weight: Crude oil contains a much wider range of hydrocarbon molecules, including very heavy and complex ones, while natural gas is dominated by light, low molecular weight hydrocarbons.

3. Non-Hydrocarbon content: Both contain non-hydrocarbons, but the types and proportions can differ. For instance, natural gas can have significant amounts of non- combustible gases like CO2 and N2.

Economic Benefits of Oil and Gas in Ghana

₁. Source of income (Money): The oil and gas industry give the Ghanaian government a lot of money. This comes from taxes, fees (called royalties), and the government’s share in oil projects. This money helps Ghana pay for schools, roads, hospitals, and other important national projects. Experts say Ghana could earn up to $21 billion from oil and gas between 2015 and 2030.

2. Growth of the economy (GDP): When Ghana started selling oil in 2011, the economy grew very fast. This helped make Ghana one of the fastest-growing countries in Africa at that time. When Ghana earns more money from oil, the economy improves.

3. More products to export: Before oil, Ghana mostly exported gold and cocoa. Now, Ghana also exports oil, which gives the country more ways to earn money from other countries.

4. Earning foreign currency: Selling oil to other countries helps Ghana earn foreign money (like US dollars), which is needed for buying goods from other countries and keeping the Ghana cedi stable.

5. Creating jobs: The oil and gas industry gives jobs to many Ghanaians. People work in oil drilling, transportation, security, and support services.

6. Improving roads and buildings (Infrastructure): Some of the money from oil is used to build roads, schools, electricity lines, and water systems. This makes life better and helps businesses work more efficiently.

7. Bringing in investors: Because Ghana has oil and gas, many international companies are coming to invest. These companies bring money, machines, and skilled workers, which help grow the economy. The government is also making the industry fair and open so more investors will feel safe doing business in Ghana.

How Oil And Gas Are Changing Ghana’s Energy

Sector ₁. Making electricity (Power generation): Ghana uses natural gas from oil production to make electricity. This is better than relying only on water (hydropower) or expensive fuels like diesel. Gas makes electricity more reliable and may cost less in the future.

2. Helping factories work better (Industrial growth): Some factories get natural gas at lower prices (subsidies), which helps them save money and work more efficiently.

These include factories that make fertiliser, ceramics, and petrochemicals. In the future, even more factories, like those in mining, may also use gas.

3. LPG for cooking and business: Natural gas is used to make LPG (Liquefied Petroleum Gas). This is used in homes and businesses for cooking. The government wants more people to use LPG because it is cleaner and safer than wood or charcoal.

Impact of oil and gas discoveries in Ghana

1. Environmental damage Damage Causes Impact Oil spills This is as a result of accidents caused during drilling, transportation (tanker accidents), or pipeline leaks.

1. Devastate marine ecosystems, harming or killing fish, seabirds, marine mammals, and coastal vegetation.

2. Pollute beaches and coastal areas, affecting tourism and fishing industries.

3. Long-term damage to ecosystems, as oil can persist in sediments for years.

Water pollution

1. Wastewater discharge from drilling operations, containing drilling fluids, heavy metals, and other pollutants.

2. Contamination of

groundwater from fracking operations (if applicable).

1. Harm aquatic life.

2. Make water unsuitable for drinking or agriculture.

3. Damage local ecosystems.

Air pollution

1. Emissions from drilling rigs, refineries, and associated transportation.

2. Release of methane (a potent greenhouse gas) during extraction and processing.

3. Flaring of natural gas (burning off excess gas), which releases pollutants.

1. Contribute to respiratory problems and other health issues.

2. Worsen air quality.

3. Contribute to climate change.

Habitat destruction

1. Construction of drilling platforms, pipelines, roads, and other infrastructure.

2. Deforestation and land clearing.

1. Destroy natural habitats, displacing wildlife.

2. Fragment ecosystems, reducing biodiversity.

3. Damage coastal ecosystems like mangroves, which are important for fisheries and coastal protection.

Figure 2.2: Crude oil spillage destroys aquatic life

2. Social Impacts

Crude oil in Ghana has generated mixed social impacts, balancing national economic growth with significant local disruptions. While creating jobs, contributing over billion in revenue since 2011, and fostering infrastructure in host communities, it has also caused some negative impacts. In some communities, the discovery of oil and gas has made the cost of living (like food and housing) more expensive and strained fishing livelihoods. It can also lead to social problems such as crime, unsafe behaviours, and conflicts among people.

3. Revenue Management

The money Ghana earns from oil and gas must be used properly and shared fairly. If the money is wasted or misused, it can lead to what is called the “resource curse”, where a country becomes poor even though it has valuable resources.

Good planning helps the country grow and develop in the long term.

Uses of Natural Gas

₁. Producing electricity: In power plants, natural gas is burned to produce steam, which turns turbines to generate electricity. Natural gas produces less pollution than coal or oil, which helps protect the environment. It is also more flexible, as gas power plants can be turned on or off quickly depending on how much electricity is needed. In Ghana, natural gas helps provide power for homes and industries.

2. Natural gas is also used for heating: It is also used in industries that need high temperatures for making products. It is cleaner, cheaper and more efficient source of heat.

3. In cooking: Natural gas gives a strong and clean flame, which makes cooking easier and faster. Many people and restaurants prefer gas stoves because they can control the heat well. In Ghana, LPG is the most common gas used for cooking in homes. It is safe, easy to use, and widely available in cylinders.

4. In factories and industries, natural gas is used as a raw material to make products:

Naturals gas helps make fertilisers, which are important for farming. It also helps in producing chemicals like methanol and ammonia, and hydrogen used in fuel and refining processes. Using natural gas in industry can help Ghana create jobs, produce more goods locally, and grow its economy.

5. Natural gas can also be used in transportation: Compressed Natural Gas (CNG) is a type of fuel used in vehicles like buses and taxis. It is cleaner and eco-friendly than petrol and diesel, and it helps reduce air pollution. It is composed primarily of methane and created by compressing natural gas to less than 1% of its atmospheric volume.

Key questions: What are the various processes involved in the separation of crude oil into its component fractions for use?

Processes Involved In Extraction Of Oil And Gas

The extraction of oil and gas involves several important steps. Each stage is necessary to safely bring these resources from deep underground to the surface where they can be used.

The process includes exploration, drilling, well completion, and production.

1. Exploration: The first step is exploration, which focuses on finding underground areas that may contain oil or gas. Scientists begin by using seismic surveys, where sound waves are sent into the ground and their echoes are recorded. These echoes help create images of the earth’s layers, which geologists study to spot places where oil or gas might be trapped.

2. Exploratory drilling: If the images from the seismic surveys look promising, the next step is exploratory drilling. A test well is drilled to check if oil or gas is really there.

This helps experts learn about the size, depth, and quality of the reservoir. This part of the process is expensive and risky because there is no guarantee that oil or gas will be found.

3. Drilling: Once oil or gas is found, the next step is drilling a deeper and proper well to reach the reservoir. A drilling rig, which is a large machine, is used to make a hole in the ground. At the end of a long pipe, there is a drill bit, a strong cutting tool that breaks through rocks. During drilling, a special liquid called drilling mud is pumped down to cool the drill bit, bring up crushed rock, and keep the well stable. In many cases, directional drilling is used to drill at an angle or even horizontally. This method helps reach more oil or gas with fewer wells. In Ghana, both land-based (onshore) and sea-based (offshore) drilling operations take place. These require skilled workers and advanced equipment.

4. Well completion: After the drilling is done, the well must be prepared to safely extract oil or gas. This step is called well completion. Steel pipes known as casings are put into the well and cemented in place. This makes the well strong and prevents oil, gas, or water from leaking.

5. Perforation: Perforation is a well-completion process that creates tunnels through the steel casing, cement, and into the target rock formation using explosive-shaped charges. This establishes a vital conduit for oil and gas to flow from the reservoir into the wellbore. It is generally performed after the well is drilled and cased. In some cases, a process called hydraulic fracturing (fracking) is used. This involves pumping or injecting fluid at high pressure into the rock to create cracks. These cracks make it easier for the oil or gas to flow.

6. Production: The final stage is production, where oil and gas are brought to the surface.

In the beginning, the natural pressure inside the reservoir is enough to push the oil or gas out. This is called primary recovery. But as pressure drops, less oil comes out.

To get more oil, secondary recovery is used. Water or gas is pumped into the reservoir to push the oil or gas towards the well. In difficult cases, enhanced oil recovery (EOR) methods are used. These include injecting heat, gas, or chemicals to make the oil flow more easily. Ghana uses different methods depending on the type of reservoir, aiming to get as much oil or gas out as possible.

7. Transportation: Once extracted, oil and gas must be transported from the production site to refineries, processing plants, and consumers.

Pipelines: These are the most common and efficient way to transport large volumes of oil and gas over long distances, both onshore and offshore.

Tankers: Ships are used to transport oil and liquefied natural gas (LNG) across oceans.

LNG is natural gas that has been cooled to a liquid state to reduce its volume for transportation. Tank trucks are used to transport smaller volumes of oil and gas over shorter distances. Ghana utilises pipelines to transport oil and gas within the country and tankers for exporting oil to international markets.

8. Processing: Raw oil and gas need to be processed to make them usable. Crude oil is refined in refineries to separate it into various petroleum products, such as gasoline, diesel fuel, jet fuel, heating oil, and asphalt. Natural gas is processed to remove impurities such as water vapour, carbon dioxide, hydrogen sulphide, and other gases.

It may also be separated into its components, such as methane (the main component of natural gas), ethane, propane, and butane. Ghana has refineries such as Tema Oil Refinery to process crude oil and gas processing plants to prepare natural gas for distribution and use in the country.

Hydraulic fracturing (Fracking) Fracking is a special method used to get oil and natural gas out of rocks that are very hard and do not let fluids flow through them easily. Think of it like trying to get juice out of a very tight sponge - you need to create cracks to let the juice flow out.

How does fracking work? (Step-by-step process)

Step 1: Drilling the well Fracking begins with drilling a deep hole from the surface of the ground down to a rock layer that contains oil or natural gas. This hole can be drilled straight down (vertical drilling) or sideways underground (horizontal drilling). Horizontal drilling is often preferred because it allows access to more of the oil- or gas-rich rock. This step is important because it creates a pathway to reach the oil and gas trapped deep underground. It is like inserting a straw into a bottle to reach the liquid at the bottom.

Step 2: Strengthening the well (Casing and cementing) After drilling, steel pipes known as casings are placed inside the hole to keep it strong and stable. Then, cement is poured around the casing to seal the well. This prevents the well from collapsing and stops harmful substances from leaking into underground water supplies used for drinking. This step also ensures that the oil and gas will flow through the correct path. It can be compared to placing a strong pipe inside a wall and sealing it with concrete to prevent leaks.

Step 3: Injecting fracturing fluid Next, a mixture of water, sand, and chemicals (e.g., hydrochloric acid, acetic acid and isopropanol) is pumped into the well at very high pressure. This pressure causes the surrounding rock to crack, creating small pathways for the oil and gas to move through.

The fluid mixture usually contains about 90% water, sand to keep the cracks open, and a small amount of chemicals. These chemicals serve different purposes: reducing friction, thickening the fluid, killing bacteria, and protecting the metal pipes from rust. This process is similar to using a high-pressure hose to break ice, then placing small objects into the cracks to keep them open.

Step 4: Keeping cracks open with sand (Proppants) The sand particles, also called proppants, are carried by the fluid into the cracks in the rock.

When the pressure is removed, the sand stays inside the cracks and keeps them open. This allows oil and gas to continue flowing through the cracks. Without the sand, the cracks would close again, like how a sponge closes after being squeezed. You can think of this as putting tiny pebbles in a door crack to keep it from closing.

Step 5: Oil and gas production In the final step, the pressure inside the well is gradually reduced. This allows oil and gas to begin flowing up the well to the surface. Some of the water mixture also returns to the surface. This is called flowback water. Along with the oil and gas, substances such as salts, minerals from the rocks, and sometimes naturally occurring radioactive materials may also come up. It is very important that the used water is properly handled and treated to avoid environmental pollution.

Importance of fracking ₁. Accessing Oil and Gas from Hard-to-Reach Rocks: Before the introduction of fracking, oil and gas trapped deep inside tight rock formations could not be extracted.

Fracking has made it possible to break open these rocks, allowing the oil and gas to flow out. This process has significantly increased the availability of oil and gas around the world.

2. Getting more from each well: Fracking not only helps in accessing difficult-to-reach resources but also improves the performance of oil and gas wells. It allows each well to produce more oil and gas over a longer period of time. As a result, companies get better returns from their drilling efforts, making the entire process more efficient and profitable.

3. Increasing energy independence: Through fracking, countries can produce more of their own oil and gas. This reduces the need to import energy from other nations and makes a country less affected by global price changes. Producing energy locally also strengthens national security and supports stable energy supplies.

4. Creating jobs and supporting the economy: Fracking supports job creation in several areas. Workers are needed for drilling, transporting materials, operating equipment, and providing other support services. As more people are employed, income increases in communities, and local economies benefit through increased spending and development.

Activity 2.1 Oil refining simulation Aim: To understand how crude oil is separated into different products through fractional distillation What you need

• Cooking oil (vegetable oil)

• Water

• Food colouring (red, blue, yellow, green)

• Clear plastic bottles (5-6 different sizes)

• Measuring cups

• Funnel

• Labels and markers

• Thermometer (if available)

• Hot water from the kitchen

• Ice cubes What to do

1. Mix the crude oil simulation

a. 200ml cooking oil

b. 50ml water

c. Add different food colourings to represent different hydrocarbons:

• Red drops represent Heavy fuel oil

• Blue drops represent Diesel

• Yellow drops represent Kerosene

• Green drops represent Petrol/gasoline

d. Shake well to create your “crude oil” mixture

2. Temperature-based separation

a. Cold separation (simulating light fractions)

i. Pour the mixture into a clear bottle

ii. Add ice cubes around the bottle

iii. Wait 10 minutes and observe layers forming

iv. Record: Which colours separate first?

b. Warm separation (simulating heavy fractions)

i. Warm another portion in a hot water bath

ii. Observe how heating affects the mixture

iii. Record: How does temperature change the separation?

Write down your response and share it with your friends.

3. Density separation

a. Create density tower

i. In a tall, clear container, slowly layer

• Bottom: Coloured water (heaviest - represents heavy fuel oil)

• Middle: Thick oil mixture (represents diesel/kerosene)

• Top: Light oil (represents petrol)

b. Observe and record

i. Which products settle at different levels?

ii. How does this relate to real oil refining?

Write down your response in your notebook and share it with your friends.

Activity 2.2 Debate on Crude Oil

Perform this activity in a group of ten members.

Aim: To develop an evidence-based argument on the usefulness and economic necessity of oil and gas discovery in Ghana, using economic data, policy reports, and examples from oil-producing regions.

What to do: Watch a video from the following link: https://youtu.be/kYeHOi2wb8U Use information from the video and from earlier in these learning materials to produce a one-page mind-map or poster summarising the use, necessity and impact of crude oil and natural gas use in Ghana.

Then, form small groups of 3-5 people. Share ideas and draw conclusions of the impact of the oil find on Ghana’s economy and the way forward; facilitate healthy debate. Do any of you completely oppose the burning of fossil fuels in Ghana? Conversely, are any of you very pro- fossil fuels? Compare points of view and respect one another’s standpoints.

Activity 2.3 Create a flowchart of the oil refinery process Use the information above, as well as any other available resources (the internet or textbooks), to produce a short flow diagram of the oil refinery process. Include brief descriptions of what happens at each step.

See Annex 2.0 on page xxxx for an example solution

1. List the four main types of hydrocarbons found in crude oil.

2. Analyse three environmental impacts of oil and gas extraction and explain their causes.

3. Ghana is developing a 20-year energy strategy that balances economic growth, energy security, and environmental protection. As an energy consultant, design a comprehensive plan that optimises the use of Ghana’s oil and gas resources while transitioning toward renewable energy.