Chemistry: Hydrocarbons and Reactions

Key Terms and Concepts

• Hydrocarbon: Compounds composed exclusively of hydrogen and carbon atoms, bonded covalently.
• Fractional Distillation: A separation process where crude oil is divided into different compounds based on boiling points.

Neutralisation Reaction

• Forms a salt that can be either soluble or insoluble.
• Example: Reaction between sulphuric acid and copper oxide produces soluble copper sulphate and water.
• Steps to produce copper sulphate:
  • Combine copper oxide and sulphuric acid in a conical flask.
  • Stir until the reaction is complete.
  • Filter off excess copper oxide.
  • Evaporate water from the solution to obtain blue crystals of copper sulphate.

Crude Oil

• A complex mixture of hydrocarbons derived from ancient biomass primarily consisting of plankton.
• Requires fractional distillation for effective use due to varying boiling points of its components.
• Process of fractional distillation:
  • Heat crude oil until it vaporizes.
  • Vapours ascend a column, cooling and condensing at varying levels.
  • Hydrocarbons condense at different temperatures based on size, creating fractions.

Characteristics of Hydrocarbons

• As carbon atom count increases:
  • Molecules grow larger and heavier
  • Boiling points rise
  • Flammability decreases
  • Viscosity increases, making liquids thicker

Alkanes and Alkenes

• Alkane: A hydrocarbon consisting of carbon to carbon single bonds (e.g., methane, ethane).
• Represented by molecular formulas like CH₄, C₂H₆, C₃H₈, C₄H₁₀.
• Alkene: A hydrocarbon with at least one carbon to carbon double bond, generally represented as CnH2n.
• Alkenes undergo addition reactions, where elements or compounds react across the double bond, changing their structure.

Cracking Process

• Used to convert long-chain hydrocarbons from crude oil into shorter, more useful hydrocarbons.
• Involves:
  • Heating alkanes to turn them into vapour.
  • Passing vapour over a hot catalyst, producing:
    • One shorter alkane (valuable as fuel)
    • One alkene (useful for making polymers).

Unsaturated Compounds

• Compounds that contain at least one carbon to carbon double bond (e.g., alkenes).
• Allow capacity for additional hydrogen atoms due to the presence of double bonds.

Explore key concepts in chemistry including hydrocarbons and neutralisation reactions. Learn about the process of fractional distillation and how it is used to separate components of crude oil. This quiz will help reinforce your understanding of these fundamental topics.