Grade 7
  1. Introduction to Chemistry  1.1. What is Chemistry?  1.2. Importance of chemistry in daily life  1.3. Branches of chemistry  1.4. Scientific Method in Chemistry  1.5. Laboratory Safety Rules and Precautions  1.6. Common Laboratory Equipment and Their Uses  1.7. Units of measurement in chemistry
  2. Matter and its properties  2.1. Definition of Matter  2.2. Classification of matter  2.3. Properties of matter  2.3.1. Physical properties  2.3.2. Chemical properties  2.4. States of matter  2.4.1. Solid state  2.4.2. Fluid state  2.4.3. Gaseous state  2.4.4. Plasma and Bose–Einstein condensates  2.5. Changes in the states of matter  2.5.1. Melting and freezing  2.5.2. Evaporation and Condensation  2.5.3. Sublimation and deposition  2.6. Density and its applications  2.7. Diffusion and its importance
  3. Elements, Compounds, and Mixtures  3.1. Definition of the element  3.2. Classification of elements  3.3. Metals, Nonmetals and Metalloids  3.4. Noble gases and their properties  3.5. Introduction to the Periodic Table  3.6. Definition of Compound  3.7. Properties of Compounds  3.8. Introduction to Chemical Formulas  3.9. Definition of Mixture  3.10. Types of mixtures  3.10.1. Homogeneous mixture  3.10.2. Heterogeneous mixtures  3.11. Difference Between Compounds and Mixtures  3.12. Solutions, Colloids and Suspensions
  4. Separation of mixtures  4.1. Need for separation of mixtures  4.2. Separation methods  4.2.1. Filtration  4.2.2. Sedimentation and decantation  4.2.3. Evaporation  4.2.4. Crystallization  4.2.5. Distillation  4.2.6. Chromatography  4.2.7. Magnetic Separation  4.2.8. Centrifugation
  5. Atomic Structure  5.1. Introduction to Atoms  5.2. Structure of the atom  5.2.1. Nucleus and electron cloud  5.3. Subatomic particles  5.3.1. Proton  5.3.2. Neutron  5.3.3. Electrons  5.4. Atomic number and mass number  5.5. Isotopes and their uses  5.6. Ions and ion formation
  6. Periodic table  6.1. Introduction to the Periodic Table  6.2. Groups and periods  6.3. Trends in the Periodic Table  6.3.1. Atomic Size  6.3.2. Metallic and non-metallic character  6.3.3. Electronegativity  6.3.4. Reactivity of the elements  6.4. Alkali metals and their properties
  7. Chemical bond  7.1. Why do atoms form bonds?  7.2. Types of chemical bonds  7.2.1. Ionic bond  7.2.2. Covalent bond  7.2.3. Metal Bond  7.3. Properties of Ionic and Covalent Compounds  7.4. Intermolecular forces
  8. Chemical reactions  8.1. Introduction to Chemical Reactions  8.2. Signs of a chemical reaction  8.3. Types of Chemical Reactions  8.3.1. Combination Reactions  8.3.2. Decomposition reactions  8.3.3. Displacement reactions  8.3.4. Double displacement reactions  8.3.5. Combustion reactions  8.4. Law of conservation of mass  8.5. Balancing simple chemical equations
  9. Acids, Bases and Salts  9.1. Definition of Acid and Base  9.2. Properties of Acids  9.3. Properties of bases  9.4. pH Scale and Indicators  9.5. Neutralization reactions  9.6. Common Acids and Bases in Everyday Life  9.7. Preparation and use of salts  9.8. Strong and weak acids and bases
  10. Solutions and Solubility  10.1. Definition of Solution  10.2. Components of the solution  10.2.1. Solvent  10.2.2. solute  10.3. Factors Affecting Solubility  10.4. Concentration of solutions  10.5. Saturated and unsaturated solutions  10.6. Colloids and suspensions  10.7. Solubility curve and its interpretation
  11. Air and atmosphere  11.1. Composition of air  11.2. Properties of gases in the air  11.3. Importance of Oxygen and Carbon Dioxide  11.4. Air pollution and its effects  11.5. Greenhouse effect and global warming  11.6. Ways to reduce air pollution  11.7. Ozone layer and its importance
  12. Water and its importance  12.1. Properties of Water  12.2. Water as the universal solvent  12.3. Importance of water for life  12.4. Water pollution and its effects  12.5. Water Purification  12.5.1. Filtration  12.5.2. boil  12.5.3. Chlorination in water purification  12.5.4. reverse osmosis  12.6. Hard and soft water  12.7. Water cycle and its importance
  13. Fuel and energy  13.1. Types of fuel  13.1.1. Fossil fuels  13.1.2. Renewable energy sources  13.2. Combustion and energy release  13.3. Global warming and its effects  13.4. Alternative sources of energy  13.5. Ways to conserve energy
  14. Metals and Nonmetals  14.1. Physical and chemical properties of metals  14.2. Physical and Chemical Properties of Non-Metals  14.3. Difference Between Metals and Nonmetals  14.4. Uses of metals and nonmetals  14.5. Corrosion of metals and its prevention  14.6. Alloys and their importance
  15. Plastics and polymers  15.1. Natural and synthetic polymers  15.2. Properties of plastics  15.3. Biodegradable and Non-Biodegradable Plastics  15.4. Environmental impact of plastic  15.5. Recycling and waste management in plastics and polymers  15.6. Daily Uses of Polymers
  16. Introduction to Organic Chemistry  16.1. Basic definitions of organic chemistry  16.2. Carbon Compounds in Daily Life  16.3. Hydrocarbons  16.4. Simple functional groups (alcohols and carboxylic acids)  16.5. Importance of organic compounds in industry

Grade 7 ↓


Fuel and energy


Welcome to the fascinating world of fuel and energy in chemistry. In this topic, we will learn about different types of fuels, how they produce energy, and their impact on our environment. We will explore these concepts in detail with examples and simple explanations.

What are fuels?

Fuels are substances that release energy when burned. This energy can be in the form of heat, light or kinetic energy. We use different types of fuel in our daily lives to run cars, heat homes and generate electricity.

Types of fuel

There are many types of fuel, but they can generally be classified into two main groups: fossil fuels and renewable fuels.

Fossil fuels

Fossil fuels are energy sources made from the remains of dead plants and animals that lived millions of years ago. These include:

  • Coal - A black or brownish-black rock that is burned for fuel. It has historically been a major source of electricity production.
  • Petroleum - also called crude oil, is a liquid found beneath the Earth's surface. It is refined to produce gasoline, diesel, and other products.
  • Natural gas - gas composed primarily of CH 4 (methane). It is used for cooking, heating and electricity generation.

Visual example: A simplified diagram of a fossil fuel-powered power plant.

Fossil plant

Renewable fuels

Renewable fuels come from resources that don't run out even when you use them. They're generally more environmentally friendly. These include:

  • Biomass - organic matter derived from plants and animals that can be used as fuel. For example, wood, crop waste and manure.
  • Ethanol - A type of alcohol produced from the fermentation of crops such as corn and sugar cane.
  • Solar energy - obtained from the sun using solar panels, it does not run out and is constantly replenished.
  • Wind energy - generated using wind turbines that convert the kinetic energy of the wind into electricity.

These resources provide a continuous supply of energy and are sustainable over a long period of time.

How energy is produced from fuel

Fuels release energy through a process called combustion. When a fuel burns, it reacts with oxygen present in the air, producing heat and often light. The general chemical reaction for burning (combustion) of a fuel is:

        Fuel + O 2 → CO 2 + H 2 O + Energy

Let's look at the combustion of natural gas (methane):

        CH 4 + 2O 2 → CO 2 + 2H 2 O + Energy

This equation shows that when methane burns in the presence of oxygen, it forms carbon dioxide, water and releases energy.

Uses of fuel

Fuels are essential in many aspects of daily life. Here are some of their uses:

  • Transportation - Fuels such as gasoline and diesel power vehicles such as cars, trucks and airplanes.
  • Heating - Natural gas and heating oil are commonly used to heat homes and buildings.
  • Electricity generation - Power plants burn coal, natural gas or oil to generate electricity for homes and industry.
  • Industrial processes - Fuel is used to make products such as steel, cement and chemicals.

Energy from fuel

The energy produced by fuel can be converted into various forms, such as mechanical energy, thermal energy, and electrical energy.

Visual example: A diagram of energy transformation.

Chemical Thermal Mechanical Electrical

Environmental impact of fuel

Fuels are important for the energy needs of society, but they also have some impact on the environment. Let's take a look at some of these:

Air pollution

Burning fossil fuels releases pollutants such as sulfur dioxide (SO 2), nitrogen oxides (NO x) and particulate matter into the atmosphere. These pollutants can cause smog and acid rain, which affect human health and the environment.

Greenhouse gas emissions

Carbon dioxide (CO 2) and methane (CH 4) emitted by burning fuels contribute to the greenhouse effect, which causes global warming and climate change.

Visual example:

An illustration of greenhouse gas emissions reaching the atmosphere and trapping heat.

Options and solutions

People and governments are moving towards clean energy sources to reduce the impact on the environment. Here are some options and solutions:

  • Energy efficiency – using technology and practices that require less energy, such as energy-efficient appliances and better insulation for homes.
  • Renewable energy – investing in technologies that use solar, wind, hydro and geothermal energy.
  • Carbon capture and storage – capturing carbon emissions produced by the burning of fuels and storing them underground to prevent them from entering the atmosphere.

Conclusion

Fuels are a fundamental part of modern life, powering transport, heating and industry. Understanding how fuels burn and the types of fuels available is essential for making informed decisions about energy use. By exploring alternatives and adopting renewable resources, we can work towards a more sustainable future with a lower environmental footprint.


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