Summary

• Description:

  The PDF document comprises The Elites Jet Chemistry Paper 3 2025 Mock Exam with Marking Scheme.

  It is a KCSE Chemistry (Practicals) Paper 3 (233/3) Pre-Mock March 2025 examination.

  • Duration: 2¼ Hours
  • Total Marks: 40
  • Number of Questions: 3 (Questions 1–3)
  • Marking Scheme: The marking scheme is in a different document.

  It covers the following topics:

  • Solubility and crystallisation (determining solubility of a hydrated solid at different temperatures and plotting a solubility curve)
  • Graph interpretation from experimental data (reading solubility at a given temperature and determining temperature for a given mass to dissolve)
  • Volumetric analysis (acid–base titration using phenolphthalein to determine concentration)
  • Formula determination of a hydrated compound (finding the value of n in H₂C₂O₄.nH₂O)
  • Qualitative analysis of an unknown solid (heating a solid, testing evolved gases with litmus, dissolving residue in hydrochloric acid, and reactions with aqueous ammonia)
  • Confirmatory tests using an additional reagent (reaction of the prepared mixture with a provided solid reagent)
  • Analysis of an unknown solid through simple tests (burning test, solubility in water, reaction with sodium hydrogencarbonate)
  • Oxidation test using acidified potassium dichromate(VI) and warming (inference of functional group based on colour change)
• Category:

  Mock Past Papers
• Level:

  Form 4
• Subject:

  CHEMISTRY

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