Chem chem

• What is the full electron configuration for Cl⁻?

  [Ne] 3s² 3p⁶
• What is the full electron configuration for Fe²⁺?

  [Ar] 3d⁶
• What does the third ionisation energy of manganese represent?

  It is the energy required to remove the third electron from a manganese atom.
• Which element has the lower first ionisation energy: magnesium or aluminium?

  Aluminium has the lower first ionisation energy.
• Why does aluminium have a lower first ionisation energy than magnesium?

  Aluminium has a higher atomic number, resulting in increased electron shielding and distance from the nucleus.
• What is the process used to ionise a sample of nickel in a TOF mass spectrometer?

  Electron impact ionisation.
• What does the m/z value represent in a mass spectrum?

  It represents the mass-to-charge ratio of ions.
• Which ion reaches the detector first in the TOF mass spectrometer for nickel with m/z values of 58 and 61?

  The ion with m/z = 58 reaches the detector first.
• How do you calculate the relative atomic mass of nickel from the given abundances?

  Relative atomic mass = (58 * 61.0% + 60 * 29.1% + 61 * 9.9%) / 100.
• What is the formula for ethanedioic acid?

  H₂C₂O₄
• What is the significance of concordant titres in titration?

  Concordant titres are results that are close in value, indicating accuracy and reliability in the titration process.
• How do you calculate the mass of ethanedioic acid in 25.0 cm³ of solution that reacted with sodium hydroxide?

  Mass of acid = moles of acid × molar mass of acid.
• What is the homologous series to which octane belongs?

  Alkanes.
• What is the equation for the complete combustion of octane (C₈H₁₈)?

  C₈H₁₈ + 12.5 O₂ ⟶ 8 CO₂ + 9 H₂O.
• What is the IUPAC name of the isomer of octane used to improve car engine performance?

  2,2,4-trimethylpentane.
• What is the IUPAC name for compound X produced when an alkane is cracked?

  Propene.
• What is the molecular formula of the alkane that produces one molecule of compound X, one molecule of octane, and one molecule of ethene when cracked?

  C₁₂H₂₆.
• What type of cracking produces a high yield of compound X?

  Steam cracking.
• What are two conditions required for steam cracking?

  High temperature and high pressure.
• What are the types of isomers for compound X and their displayed formulas?

  • Chain isomer: (example structure)
  • Position isomer: (example structure)
  • Functional group isomer: (example structure)