Summary

• Description:

  The PDF document comprises The Elites Jet Chemistry Paper 1 2025 Mock Exam with Marking Scheme.

  It is a KCSE Chemistry (Theory) Paper 1 (233/1) Pre-Mock March 2025 examination.

  • Duration: 2 Hours
  • Total Marks: 80
  • Number of Questions: 29 (Questions 1–29)
  • Marking Scheme: The marking scheme is in a different document.

  It covers the following topics:

  • Chromatography (separating dyes/pigments; properties of dyes)
  • Preparation and reactions of gases (sulphur(IV) oxide; hydrogen sulphide; chlorine displacement in KI; nitrogen(II) oxide preparation)
  • Reactivity series and reactions with steam (magnesium vs copper; testing hydrogen gas)
  • Redox chemistry (oxidation numbers; identifying oxidation in reactions)
  • Electrolytes and electrochemistry concepts
  • Gas diffusion calculations (Graham’s law)
  • Qualitative analysis (distinguishing iron(II) chloride and copper(II) chloride solutions; complex ion formation with ammonia)
  • Separation techniques and solvent extraction
  • Periodic trends (atomic and ionic radii; metallic character and reactivity in a group)
  • Organic chemistry (homologous series; dehydration; reactions leading to sodium propanoate; decarboxylation using soda lime)
  • Stoichiometry and formula determination (combustion data to find molecular formula)
  • Chemical kinetics (effect of temperature on reaction rate)
  • Energetics (molar enthalpy of combustion; bond energy calculations; calorimetry)
  • Volumes of gases in combustion and absorption (ethane/oxygen mixture; NaOH absorption of CO2)
  • Detergents and cleaning action; hard water and scum formation
  • Alloys and percentage composition calculations (Al/Cu alloy reacting with HCl)
  • Solubility and crystallisation calculations (sodium nitrate)
  • Bunsen burner flames (types and regions/colour)
  • Naming organic compounds (IUPAC nomenclature)
  • Preparation of salts (preparing barium sulphate from a given starting material)
  • Extraction of aluminium (bauxite, concentration, cryolite and electrolysis concepts)
  • Industrial chemistry in Kenya (soda ash manufacture at Lake Magadi; trona and related salts)
• Category:

  Mock Past Papers
• Level:

  Form 4
• Subject:

  CHEMISTRY

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