G10 CHEM OPENER TERM 3 2026 MS

CHEMISTRY GRADE 10

TERM 3 OPENER EXAM 2026

MARKING SCHEME

Question 1 (10 marks)

• a) Any two valid safety precautions, 1 each. (2)

• b) i. Pipette/burette where appropriate (1); ii. Measuring cylinder (1).

• c) ΔT=75−25=50°C (1); Q=mcΔT=100×4.2×50 (1); Q=21,000 J (1).

• d) Any three controlled variables: acid concentration, acid volume, metal mass/surface area, same metal, apparatus or measurement method. (3)

Question 2 (10 marks)

• a) Gas particles have large spaces and can move closer; liquid particles are already close together. (2)

• b) Filtration (1); fractional distillation (1); paper chromatography (1).

• c) Particles gain kinetic energy and overcome attractions holding them in fixed positions. (2)

• d) Magnet removes iron (1); dissolve salt and filter sand (1); evaporate/crystallise filtrate for salt (1).

Question 3 (12 marks)

• a) 1=first/outer electron shell; 2=second shell; 3=second shell marker/region; 4=third shell. Examiner: accept shell identification based on the diagram's intended labels. (4)

• b) 12 protons (1); 12 electrons (1); 2.8.2 (1).