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 → Plastics and polymers ↓


Recycling and waste management in plastics and polymers


In our world, plastics and polymers play a vital role in our daily lives. From the toys we play with to the bottles we drink water from, plastic is everywhere. As useful as plastic is, it can also cause many problems if we do not manage it properly.

When we throw away plastic items, they don't disappear. Instead, they become garbage. If this waste is not handled properly, it can harm the environment. That's why it's very important to understand plastic recycling and waste management.

What is plastic?

Plastic is a material made from polymers. Polymers are large molecules made by joining many smaller molecules called monomers. Think of a polymer as a chain, and the monomers are the links in the chain. A polymer can have thousands of such links.

Here's a simple visual example of a polymer chain:

There are many types of plastic. Some are soft and flexible, like the plastic used in grocery bags. Some are hard and strong, like the plastic used in football helmets.

The importance of recycling

Recycling is the process of turning waste into new products. When we recycle plastic, we help the environment. Recycling reduces the need to make new plastic. Making new plastic requires raw materials and energy, which can harm the environment.

The recycling process works as follows:

  1. We collect used plastic.
  2. We clean them and sort them by type.
  3. These are cut into small pieces.
  4. These pieces are melted to make new plastic products.

Types of plastic waste

Not all plastics are the same when it comes to recycling. Here are some common types of plastic and their recycling possibilities:

  • Polyethylene terephthalate (PET): Commonly used in beverage bottles and food containers. This type is easy to recycle.
    C 10 H 8 O 4
  • High-density polyethylene (HDPE): Found in milk jugs and cleaning product bottles. It's easy to recycle.
    C 2 H 4
  • Polyvinyl chloride (PVC): Used in pipes and credit cards. It's difficult to recycle.
    C 2 HCl
  • Low-density polyethylene (LDPE): Used in plastic bags and wraps. It can be recycled, but is not always accepted by programs.
    C 2 H 4

Challenges in recycling

Although recycling is beneficial, it is not easy. Several challenges make it difficult to recycle plastic:

  • Contamination: Plastic mixed with food or other waste is difficult to recycle.
  • Sorting: Different types of plastics need to be sorted, which can be a time-consuming and costly task.
  • Complex products: Some products are made from different types of plastic, making them difficult to recycle.

Waste management techniques

There are other ways to manage plastic waste besides recycling:

  1. Landfilling: This is a common method in which waste is buried in the ground. However, plastic does not decompose quickly in landfills.
  2. Incineration: This involves burning waste in a controlled environment. This reduces the volume of waste, but may release harmful gases.
  3. Biodegradable plastics: Scientists are developing plastics that can decompose naturally, solving some of the problems associated with conventional plastics.

What can we do

As students, there are many things you can do to help manage plastic waste:

  • Reuse plastic: Before you throw anything away, see if you can reuse it.
  • Recycle properly: Make sure you clean and sort your plastic according to local regulations.
  • Spread awareness: Tell your friends and family about the importance of recycling.

The future of plastic

Researchers and scientists continue to work on new ways to deal with plastic waste. Some are developing technology to convert plastic back into raw materials. Others are finding alternative materials that could replace plastic altogether.

One promising area is biodegradable plastics, made from natural materials such as corn starch. These plastics can decompose quickly and do not pollute the environment.

Conclusion

Plastics and polymers are an essential part of modern life, but they also pose environmental challenges. Understanding how to recycle and manage waste helps reduce plastic pollution. By taking small steps like reusing and recycling, we can make a big difference in saving our planet.

As you learn more about plastics and how to manage them, you become part of the solution for a cleaner, greener Earth. Whether it's making sure you recycle a water bottle properly or encouraging others to be mindful of plastic waste, every effort counts.

Let us all work together to create a sustainable future that strikes a balance between using these amazing materials and protecting our precious environment.


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