Grade 8
  1. Introduction to Chemistry  1.1. Nature and scope of chemistry  1.2. Importance of chemistry in daily life  1.3. Chemistry and its relation with other sciences  1.4. The role of chemistry in industry, medicine and the environment  1.5. Scientific investigation and experimental methods in chemistry
  2. Matter and its properties  2.1. Definition and classification of matter  2.2. Physical and chemical properties of matter  2.3. Law of conservation of matter  2.4. Extensive and Intensive Properties of Matter  2.5. Kinetic molecular theory of matter  2.6. States of matter: solids, liquids, gases, plasmas, and Bose-Einstein condensates  2.7. Changes in state and energy are involved  2.8. Diffusion and Brownian motion
  3. Elements, Compounds, and Mixtures  3.1. Definition and differences between elements, compounds, and mixtures  3.2. Atomic Structure and Atomic Number  3.3. Chemical symbols and formulas  3.4. Trends in the Periodic Table (Groups and Periods)  3.5. Classification of Elements: Metals, Nonmetals and Metalloids  3.6. Rare Earth Elements and Transition Metals  3.7. Types of mixtures: homogeneous and heterogeneous  3.8. Separation of Mixtures Using Physical and Chemical Methods
  4. Separation Techniques  4.1. Filtration, Sedimentation and Decantation  4.2. Evaporation and crystallization  4.3. Distillation and Fractional Distillation  4.4. Chromatography and its applications  4.5. Sublimation in the purification of compounds  4.6. The role of centrifugation in biochemical processes
  5. Atomic Structure  5.1. Dalton's atomic theory  5.2. Structure of the atom: protons, neutrons and electrons  5.3. Bohr's atomic model  5.4. Introduction to Quantum Mechanical Model  5.5. Electron Configuration and Energy Levels  5.6. Excitation and emission spectra  5.7. Isotopes and their applications
  6. Periodic Table and Chemical Trends  6.1. History and Development of the Periodic Table  6.2. Modern periodic law  6.3. Periodicity and trends in atomic and ionic sizes  6.4. Ionization Energy, Electron Affinity and Electronegativity  6.5. Introduction to Lanthanides and Actinides  6.6. Application of periodic trends in chemistry
  7. Chemical Bonding and Molecular Structure  7.1. Types of chemical bonds: ionic, covalent and metallic bonds  7.3. Polar and Nonpolar Molecules  7.4. Hydrogen bonding and its applications  7.5. Intermolecular forces: dipole-dipole, London dispersion force
  8. Chemical Reactions and Stoichiometry  8.1. Chemical Equations and Balance  8.2. Types of Chemical Reactions: Combination, Decomposition, Displacement and Redox  8.3. Introduction to stoichiometry and the mole concept  8.4. Limiting reactant in chemical equations  8.5. Reaction rate, catalyst, and factors affecting reaction rate
  9. Acids, Bases and Salts  9.1. Definition and Properties of Acids and Bases  9.2. Strong vs. Weak Acids and Bases  9.3. pH Scale and pH Calculation  9.4. Neutralization reactions  9.5. Buffer solutions and their importance  9.6. Applications of Acids, Bases and Salts in Daily Life
  10. Solutions and Solubility  10.1. Definition of Solution, Solute, and Solvent  10.2. Factors Affecting Solubility  10.3. Concentration units: molarity and molality  10.4. Saturated, unsaturated and supersaturated solutions  10.5. Concept of osmosis and reverse osmosis  10.6. Concentrative properties of solutions
  11. Gases and Gas Laws  11.1. Properties of gases  11.2. Introduction to Ideal and Real Gases  11.3. Boyle's Law, Charles' Law and Avogadro's Law  11.4. Ideal Gas Equation and Its Applications  11.5. Application of Gas Laws in Real Life
  12. Thermochemistry and energy transformation  12.1. Energy in Chemical Reactions  12.2. Exothermic vs. Endothermic Reactions  12.3. Heat and Enthalpy Changes  12.4. Calorimetry and heat transfer in reactions
  13. Metals and Nonmetals  13.1. Physical and Chemical Properties of Metals and Nonmetals  13.2. Reactivity Series of Metals  13.3. Corrosion and its prevention  13.4. Extraction of metals from ores  13.5. Uses of metals and non-metals in daily life
  14. Introduction to Organic Chemistry  14.1. Characteristics of carbon and organic compounds  14.2. Functional groups and their importance  14.3. Simple Hydrocarbons: Alkenes, Alkenes and Alkynes  14.4. Isomerism in organic compounds  14.5. Introduction to polymers and their uses
  15. Environmental Chemistry and Sustainability  15.1. Green Chemistry Principles  15.2. Effects of Chemical Pollution on Ecosystems  15.3. Acid rain and its effects  15.4. Ozone layer depletion and global warming  15.5. Waste Management and Recycling in Chemistry

Grade 8 ↓


Environmental Chemistry and Sustainability


Environmental chemistry is the scientific study of the chemical and biochemical phenomena that occur in the environment. It is a multidisciplinary field that includes atmospheric, aquatic, and soil chemistry, as well as relying heavily on analytical chemistry and being linked to other areas of environmental science. By understanding the chemical processes and changes in the environment, we can develop ways to make human activity more sustainable and reduce its negative impacts.

What is environmental chemistry?

Environmental chemistry helps us understand how chemicals move through ecosystems and how they affect the environment and human health. It involves the study of the sources, reactions, transport, effects, and fates of chemical species in various environmental media such as water, air, and soil.

Example: Water pollution

When chemicals from industries are released into nearby rivers, they can contaminate water supplies. A common contaminant is Hg or mercury, which can accumulate in fish and pose health risks to humans and wildlife that eat the fish.

The importance of sustainability

Sustainability in environmental chemistry means finding ways to reduce our chemical impact on the planet while meeting societal needs. This includes managing resources efficiently and responsibly so that future generations can also meet their needs.

The concept of sustainability is often represented by this balancing act:

Society Environment Economy

Example: Reduce, reuse, recycle

One of the simplest approaches to sustainability is the "three R's": reduce, reuse, and recycle. By reducing the amount of materials we consume, reusing items instead of throwing them away, and recycling materials, we can help reduce our environmental footprint.

Common chemicals in the environment

Various chemicals are found in the environment, some of which are naturally occurring and some are produced due to human activities.

  • Nitrogen: Nitrogen, found as N_2, is important for plant growth and is found in abundance in the atmosphere.
  • Carbon dioxide: Represented as CO_2, it is released into the atmosphere through processes such as respiration and the burning of fossil fuels.
  • Ammonia: Known as NH_3, is commonly used in fertilizers and can cause nutrient pollution in water bodies.

Example: Carbon cycle

The carbon cycle describes how carbon atoms move through the environment:

Photosynthesis: CO_2 + H_2O → C_6H_12O_6 + O_2
Respiration: C_6H_12O_6 + O_2 → CO_2 + H_2O

Effects of chemicals on the environment

Although chemicals are essential for life, their imbalance or the entry of harmful substances can have negative effects on the environment, such as pollution.

Example: Acid rain

Acid rain is caused by emissions of sulfur dioxide (SO_2) and nitrogen oxides (NO_x) that react with water molecules in the atmosphere to produce acids.

SO_2 + H_2O → H_2SO_4 (sulphuric acid)
NO_x + H_2O → HNO_3 (nitric acid)

Measurement of environmental chemicals

Environmental chemists use a variety of methods to measure the concentrations of different chemicals in different environments. Techniques such as gas chromatography and mass spectrometry can provide extensive information about chemical composition.

Example: Testing the pH level

pH measurement is a simple technique to test the acidity or alkalinity of a solution. A pH less than 7 is acidic, while a pH greater than 7 is alkaline.

Promoting environmental sustainability

To promote sustainability, both individuals and industries should adopt environmentally friendly practices. This can include using sustainable energy sources, reducing waste, and implementing pollution controls.

Example: Renewable energy

Renewable energy sources such as solar, wind, and hydropower provide alternatives to fossil fuels, with a reduced environmental impact.

Conclusion

Environmental chemistry and sustainability are important areas of study because they provide insight into how we interact with the natural world and how we can protect it. Understanding these concepts is essential to developing technologies and practices that support life on Earth without harming the environment.


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