F3 CHEM OPENER TERM 3 2026 MS
Document Details
Document Preview
Word Editable SampleFORM 3 TERM 3 OPENER EXAM 2026
CHEMISTRY
MARKING SCHEME
==============================================================================
QUESTION 1 MARKS: 3
(a) Dye A and Dye C (both spots align horizontally with spots in Ink X). [B1]
(b) Dye B is the most strongly adsorbed onto the paper / least soluble in the moving solvent. [B1]
(c) Testing purity of drugs/pharmaceuticals OR identifying dyes/additives in food products OR forensic ink analysis. [B1]
QUESTION 2 MARKS: 3
(a) An acid is a substance that dissociates/ionizes in water to produce hydrogen ions (H⁺) as the only positive ions. [B1]
(b) In methylbenzene (an organic non-polar solvent), hydrogen chloride exists as neutral covalent molecules and does not ionize (no H⁺ ions present) ✓1. In water (a polar solvent), HCl ionizes fully to produce hydrogen ions (H⁺ / H₃O⁺) which cause acidic properties and turn blue litmus red ✓1. [2 Marks: B1 + B1]
QUESTION 3 MARKS: 4
(a) Magnesium burns with a brilliant/blinding white flame ✓1; A white ash/solid (magnesium oxide) is formed ✓1. [2 Marks: B1 + B1]
(b) 3Mg(s) + N2(g) -> Mg3N2(s) [B1]
(c) Oxygen and nitrogen from the atmosphere chemically combine with magnesium to form solid magnesium oxide and magnesium nitride, adding mass to the original magnesium metal. [B1]
QUESTION 4 MARKS: 4
This document is professionally prepared and verified for Form 3 (Secondary (8-4-4)) • Term 3.
- Competency-driven teacher inquiry models
- Guiding questions for active learner engagement
- Real-life problem-solving applications
- Formative & summative assessment indicators
- Performance levels (Exceeding, Meeting, Approaching)
- Practical assessment task breakdowns