Grade 11
  1. Basic concepts of chemistry  1.1. Importance of Chemistry  1.2. Nature and scope of chemistry  1.3. laws of chemical combination  1.3.1. Law of conservation of mass  1.3.2. Law of definite proportions  1.3.3. Law of multiple proportions  1.3.4. Law of gaseous volume  1.3.5. Avogadro's Law  1.4. Dalton's atomic theory  1.5. Mole concept and molar mass  1.6. Percent composition  1.7. Empirical and molecular formula  1.8. Stoichiometry and Stoichiometric Calculations  1.9. Limiting reagent concept
  2. Structure of the atom  2.1. Discovery of the electron, proton, and neutron  2.2. Atomic Model  2.2.1. Thomson's model  2.2.2. Rutherford's model  2.2.3. Bohr's model  2.3. Quantum mechanical model of the atom  2.4. Dual nature of matter and radiation  2.5. Heisenberg's uncertainty principle  2.6. Quantum numbers  2.7. Atomic orbitals and their shapes  2.8. Electronic configuration of elements  2.9. Aufbau principle  2.10. Pauli's exclusion principle  2.11. Hund's maximum multiplicity rule  2.12. de Broglie's hypothesis  2.13. Photoelectric effect
  3. Classification of elements and periodicity in properties  3.1. Historical development of the periodic table  3.2. Modern Periodic Law and Periodic Table  3.3. Periodic trends in properties  3.3.1. Atomic and Ionic Radius  3.3.2. Ionization enthalpy  3.3.3. Electron gain enthalpy  3.3.4. Electronegativity  3.3.5. Valency  3.3.6. Metallic and Non-Metallic Properties  3.3.7. Oxidation states  3.4. Unusual Properties of the First Elements
  4. Chemical Bonding and Molecular Structure  4.1. Kossel–Lewis approach to chemical bonding  4.2. Ionic or electrovalent bond  4.3. Covalent bond and its features  4.4. Bond parameters  4.5. VSEPR Theory  4.6. Valence bond theory  4.7. Hybridization and its types  4.8. Molecular orbital theory  4.8.1. Bond order and stability  4.9. Hydrogen bonding
  5. States of matter  5.1. Intermolecular forces  5.2. Gas Laws  5.2.1. Boyle's law  5.2.2. Charles's Law  5.2.3. Avogadro's Law  5.2.4. Dalton's law of partial pressure  5.2.5. Graham's law of spread  5.3. Ideal Gas Equation and Applications  5.4. Real gases and deviations from ideal behaviour  5.5. Kinetic molecular theory of gases  5.6. Liquefaction of gases  5.7. Properties of Liquids  5.8. Surface tension and viscosity
  6. Thermodynamics  6.1. System and environment  6.2. Types of systems in thermodynamics  6.3. Types of procedures  6.4. First law of thermodynamics  6.5. Internal energy and enthalpy  6.6. Heat capacity and specific heat  6.7. Hess's law of constant heat summation  6.8. Bond dissociation enthalpy  6.9. Enthalpy of formation and combustion  6.10. Enthalpy of solution and neutralization  6.11. Spontaneity and the second law of thermodynamics  6.12. Gibbs free energy and its applications
  7. Balance  7.1. The concept of balance  7.2. Equilibrium constant and its applications  7.3. Le Chatelier's principle  7.4. Ionic equilibrium in solutions  7.5. Acid and Base Theory  7.5.1. Arrhenius concept  7.5.2. Bronsted-Lowry concept  7.5.3. Lewis concept  7.6. pH Scale and pOH  7.7. Common ion effect  7.8. Hydrolysis of salts  7.9. Buffer solutions and their mechanism of action  7.10. Solubility equilibrium of sparingly soluble salts
  8. Redox reactions  8.1. Oxidation and reduction concepts  8.2. Oxidation number and its applications  8.3. Redox reactions in terms of electron transfer  8.4. Balancing redox reactions (oxidation number and ion-electron methods)  8.5. Types of redox reactions  8.6. Electrochemical Cells and Redox Reactions
  9. Hydrogen  9.1. Position of Hydrogen in the Periodic Table  9.2. Isotopes of hydrogen  9.3. Preparation of Hydrogen  9.4. Properties of Hydrogen  9.5. Hydrides and their classification  9.6. Water and heavy water  9.7. Hydrogen peroxide and its properties  9.8. Uses of Hydrogen and Its Compounds
  10. S-block elements (alkali and alkaline earth metals)  10.1. Group 1 Elements - Properties and Trends  10.2. Group 2 Elements - Properties and Trends  10.3. Unusual properties of lithium and beryllium  10.4. Important compounds of sodium and their uses  10.5. Important Compounds of Magnesium and Calcium
  11. Some p-block elements  11.1. General Introduction to p-Block Elements  11.2. Group 13 Elements  11.2.1. Boron and its compounds  11.3. Group 14 Elements  11.3.1. Carbon and its allotropes  11.3.2. Important Compounds of Carbon and Silicon
  12. Organic Chemistry - Some Basic Principles and Techniques  12.1. Classification and Nomenclature of Organic Compounds  12.2. Structural representation of organic compounds  12.3. Classification of organic reactions  12.4. Electronic Effects in Organic Chemistry  12.4.1. Inductive effect  12.4.2. Resonance effect  12.4.3. Hyperconjugation  12.5. Reaction mechanism and intermediate species  12.6. Purification and qualitative analysis of organic compounds
  13. Hydrocarbons  13.1. Hydrocarbons  13.1.1. Preparation and Properties of Alkenes  13.2. alkene  13.2.1. Preparation and Properties of Alkenes  13.2.2. Electrophilic addition reactions  13.3. Alkynes  13.3.1. Preparation and Properties of Alkynes  13.4. Aromatic hydrocarbons  13.4.1. Structure and properties of benzene  13.4.2. Electrophilic substitution reactions of benzene
  14. Environmental Chemistry  14.1. Environmental Pollution  14.2. Atmospheric pollution and the greenhouse effect  14.3. Water pollution and treatment methods  14.4. Soil pollution and its effects  14.5. Industrial waste and its treatment  14.6. Strategies for pollution control

Grade 11 → Environmental Chemistry ↓


Water pollution and treatment methods


In this talk we will have an in-depth discussion on the important topic of water pollution and the various methods available to treat polluted water. This topic is important because of the growing concern about water quality and its direct impact on human health and the environment.

What is water pollution?

Water pollution occurs when harmful substances contaminate water bodies such as rivers, lakes, oceans or groundwater, making it harmful to health and the environment. These pollutants come from a variety of sources and include a variety of chemicals, pathogens and physical changes such as high temperatures and turbidity.

Main causes of water pollution

Water pollution occurs for many reasons, and understanding these is the first step toward treatment. The most common causes include:

  1. Industrial waste: Industries release huge amounts of waste that contain pollutants such as heavy metals, toxins and chemicals, which are often released into water bodies.
  2. Agricultural runoff: The use of fertilizers, pesticides and other chemicals in agriculture often produces runoff that carries pollutants into nearby water sources, causing pollution.
  3. Sewage and wastewater: Untreated or poorly treated sewage adds microbes, organic waste and chemicals to water bodies, causing pollution.
  4. Oil spills: Accidental or intentional release of oil into water bodies negatively impacts aquatic life and water quality.
  5. Plastic pollution: Plastic waste often ends up in water bodies, where it does not decompose, harming marine life and releasing toxins.

Types of water pollutants

The main types of water pollutants are:

  • Chemical pollutants: These include heavy metals such as mercury (Hg), lead (Pb), and chemicals such as pesticides and herbicides.
  • Pathogens: These are disease-causing microorganisms such as bacteria, viruses, and parasites that come from feces and animal waste.
  • Physical pollutants: This includes sediment pollution that causes turbidity and affects aquatic life.
  • Nutrients: Excessive nutrients, mainly from agricultural runoff, lead to the process of eutrophication, which reduces oxygen levels in water.
River Drainage industrial waste

Effects of water pollution

Water pollution has numerous adverse effects that widely impact human health, aquatic life and the environment.

Effects on human health

Contaminated water can cause a variety of health problems in humans, such as gastrointestinal diseases, respiratory problems, and neurological disorders. Pollutants such as lead (Pb) and arsenic (As) disrupt normal bodily functions and can cause acute poisoning.

Effects on aquatic life

Aquatic ecosystems are severely affected by water pollution. For example, oil spills settle on the feathers of birds, making them unable to fly, while fish eat chemical pollutants, which can lead to their death or mutation.

fish waste Oil layer

Eutrophication

Eutrophication is a serious problem caused by nutrient pollution. Excessive nutrients, mainly phosphorus (P) and nitrogen (N), cause excessive growth of algae that disrupts aquatic ecosystems by blocking sunlight and reducing oxygen levels. This process leads to "dead zones" where no life can survive.

Methods of treatment of water pollution

The good news is that there are various methods used to treat polluted water and bring it to a usable state. These methods are mainly divided into physical, chemical and biological treatment.

Physical treatment

  • Sedimentation: In this process suspended solids are allowed to settle out of the water by gravity. It is often used as a pre-treatment step. The water is placed in sedimentation tanks where the solids settle to the bottom.
    • Water in sedimentation tank:
----------------------
| Water              |
| Sedimentation      |
|                    |
----------------------
----------------------
| Sludge Layer       |
----------------------
  • Filtration: This method removes particles by passing water through filters made of sand, gravel or charcoal, which trap impurities.
    • Sand layer Gravel layer Charcoal Layer

Chemical treatment

  • Chlorination: The addition of chlorine (Cl_2) disinfects water by killing harmful microorganisms. This process is widely used for the treatment of drinking water.
  • Ozonation: Ozone (O_3) is a powerful oxidizing agent that decomposes organic pollutants and kills bacteria and viruses.
  • Coagulation and Flocculation: Chemicals such as alum (Al_2(SO_4)_3) are added to water, causing the particles to clump together into larger flocs that can be easily removed.
    • Water with alum:
----------------------
|                    |
| Al_2(SO_4)_3 added |
|                    |
----------------------

Biological treatment

  • Activated sludge process: This process relies on aeration and biological floc composed of bacteria, which help break down organic matter into carbon dioxide, water and energy.
  • Bioremediation: It uses special microorganisms to remove and metabolize pollutants from water.
  • Biofiltration: Contaminated water passes through a biological medium, allowing microorganisms to digest the pollutants.

Integrated water management

An integrated approach is necessary to tackle the challenges of water pollution. Integrated water resources management (IWRM) involves a holistic view of the entire water ecosystem, encompassing river basins, urban and rural areas, and industrial areas. It emphasizes sustainable practices and emphasizes recycling and reuse, which are often integral parts of water treatment systems.

Conservation efforts also play an important role. Awareness campaigns on proper waste disposal, reducing plastic use, and sustainable practices in agriculture and industry contribute significantly to reducing water pollution.

Conclusion

Water pollution is a serious threat to the environment and human health. Through an understanding of the causes, effects and treatment methods, steps can be taken to reduce this problem. By adopting physical, chemical and biological treatment methods, we can improve water quality and protect this vital resource.


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