CHEM

• What is the content area A1 about in Unit 5: Principles and Applications of Science II?

  Relating properties to uses and production of substances
• What is the amphoteric character of alumina?

  Alumina can act as both acid and base
• What is the use of Ca(OH)₂ in acidic effluent treatment?

  Neutralization of acidic effluent
• Why are transition metals, transition metal oxides, and transition metal complexes used as catalysts?

  They can speed up chemical reactions
• What is the role of vanadium(V) oxide in the contact process?

  Catalyst
• How is alumina extracted from bauxite?

  Through purification and extraction processes
• What is the Hall-Héroult process used for?

  Extraction of aluminium from alumina
• What is the difference between a diaphragm cell and a membrane cell in the electrolysis of brine?

  Diaphragm cell uses a diaphragm to separate the anode and cathode, while a membrane cell uses a membrane
• What are the types of alkanes and alkenes?

  • Straight-chain alkanes and alkenes
  • Branched alkanes and alkenes
  • Cyclic alkanes and alkenes
• What is the general formula for alkanes?

  CₙH₂ₙ₊₂
• What is the IUPAC nomenclature for organic compounds?

  International Union of Pure and Applied Chemistry nomenclature
• What is the difference between sigma and pi-bonding in alkanes and alkenes?

  Sigma bonds are formed by end-to-end overlap of atomic orbitals, while pi bonds are formed by side-by-side overlap of atomic orbitals
• What is the hybridization of carbon atoms in alkanes and alkenes?

  Sp³ hybridization in alkanes and sp² hybridization in alkenes
• How do the boiling points of alkanes change with chain length?

  Boiling point increases with chain length due to increased intermolecular forces of attraction
• What are the mechanisms of hydrocarbon reactions?

  • Free radical substitution in alkanes
  • Electrophilic addition of water, halogens, hydrogen halides, and sulfuric acid in alkenes
• What is the stability of carbocations?

  Carbocations are unstable and tend to rearrange to form more stable species
• What is the use of free radical polymerization of alkenes?

  Production of polymers
• What is the process of cracking of hydrocarbons?

  Breaking down of large hydrocarbon molecules into smaller molecules
• What is the combustion of alkanes?

  Reaction of alkanes with oxygen to produce carbon dioxide and water
• What is the Kelvin scale of temperature?

  Temperature scale that starts at absolute zero
• What is the definition of enthalpy change, ∆H?

  ∆H = ∆U + p∆V
• What are the standard conditions for enthalpy change?

  1 × 10⁵ Pa, 298 K, and per mole (mol⁻¹)
• What is the system and surroundings in the context of enthalpy change?

  The system is the region where the reaction occurs, and the surroundings are the region outside the system
• What is the sign convention for enthalpy change?

  Exothermic reactions have a negative ∆H, and endothermic reactions have a positive ∆H
• What is the difference between exothermic and endothermic reactions?

  Exothermic reactions release heat, while endothermic reactions absorb heat
• What are the definitions of standard enthalpy changes related to reactions?

  • Combustion
  • Formation
  • Hydration
• How is the enthalpy change measured?

  Through the use of specific heat capacity of water and the equation heat Q = mc∆T