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 → Introduction to Organic Chemistry ↓


Simple Hydrocarbons: Alkenes, Alkenes and Alkynes


In the world of chemistry, hydrocarbons are a fascinating and essential topic. These compounds are the basic building blocks of life and are composed primarily of carbon and hydrogen atoms. Hydrocarbons can be found in everything from gasoline to plastics, and they form the basis of organic chemistry. In this article, we'll explore three simple but important types of hydrocarbons: alkanes, alkenes, and alkynes.

What are hydrocarbons?

Hydrocarbons are organic compounds composed exclusively of hydrogen and carbon atoms. They are the simplest type of organic compounds and can be found in a variety of forms, which are classified mainly based on the type of bond between their carbon atoms. These are divided into three main types:

  • Alkenes: These hydrocarbons have only single bonds between carbon atoms.
  • Alkenes: These contain at least one double bond between carbon atoms.
  • Alkynes: These contain at least one triple bond between carbon atoms.

Hydrocarbons

Alkanes, also known as paraffins, are the simplest type of hydrocarbon. They contain single bonds between carbon atoms and are the most basic structure of hydrocarbons, often called saturated hydrocarbons because their carbon atoms are saturated with hydrogen.

General formula

The general formula for alkanes is C n H 2n+2 The number of hydrogen atoms is always two more than twice the number of carbon atoms.

Examples of alkenes

Name Formula Structure
Methane CH 4 
      H
      ,
  H – C – H
      ,
      H
Etain C 2 H 6 
    HH
    ,
    C - C
    ,
    HH
Propane C 3 H 8 
    haha
    ,
    CCC
    ,
    haha

Properties of alkenes

  • Nonpolar: Because they contain only carbon and hydrogen atoms, which have the same electronegativities, alkanes are nonpolar and do not dissolve well in water.
  • Flammable: Alkanes are commonly used as fuels because they burn vigorously in oxygen to produce carbon dioxide and water.
  • Boiling point: The boiling point of alkanes also increases with the increase in the number of carbon atoms.

Alkene

Alkenes are hydrocarbons that contain at least one double bond between carbon atoms. These compounds are also known as olefins and are unsaturated due to the presence of the double bond, which allows them to participate in reactions that saturated hydrocarbons cannot.

General formula

The general formula for alkanes is C n H 2n. This shows that alkenes have two less hydrogen atoms than alkenes with the same number of carbon atoms.

Examples of alkenes

Name Formula Structure
Ethene (Ethylene) C 2 H 4 
    HH
    ,
    C = C
    ,
    HH
Propene (Propylene) C 3 H 6 
    haha
    ,
    C = C – C
    ,
    HH

Properties of alkenes

  • Reactivity: Due to the double bond, alkenes are more reactive than alkenes and easily participate in addition reactions.
  • Polymerization: Many alkenes can polymerize to form long-chain polymers, which are important in the production of plastics.
  • Boiling point: Similar to alkanes, the boiling point of alkenes increases with the increase in the number of carbon atoms.

Alkynes

Alkynes are hydrocarbons that contain at least one triple bond between carbon atoms. These molecules are also unsaturated, and the presence of the triple bond allows for unique chemical properties and reactions.

General formula

The general formula for alkynes is C n H 2n-2. Because of the triple bond, alkynes have four fewer hydrogen atoms than alkenes with the same number of carbon atoms.

Examples of alkynes

Name Formula Structure
Ethylene (Acetylene) C 2 H 2 
    H − C ≡ C − H
Propine C 3 H 4 
    hc ≡ c − c
        ,
        HH

Properties of alkynes

  • Reactivity: Alkynes are more reactive than alkenes and alkenes because of the triple bond.
  • Acidity: Alkynes have more acidic hydrogen atoms than alkenes and alkenes.
  • Boiling point: Like other hydrocarbons, the boiling point of alkynes increases with the number of carbon atoms.

Closing thoughts

To understand the fundamental concepts of organic chemistry, it is important to understand the basic types of hydrocarbons such as alkane, alkene, and alkyne. Each type of hydrocarbon has its own specific properties and reactivity due to the different bonds present between the carbon atoms.

These compounds are an essential part of our daily lives, from the fuel that powers our vehicles to the plastic products we use every day. By learning about these simple hydrocarbons, we gain a better understanding of chemistry and its impact on the world around us.


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Simple Hydrocarbons: Alkenes, Alkenes and Alkynes

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