2025 DHS H2 Chem Prelim P4_CI

List of Apparatus and Chemicals for 2025 Y6 Prelim Practical Qn No. Label Per candidate Identity Notes 1 FA 1 250 cm3 2.0 mol dm−3 NaOH Dissolve 80.0 g of NaOH in each dm3 of solution. Care: the process of solution is exothermic and any concentrated solution is very corrosive. FA 2 250 cm3 1.0 mol dm−3 sulfuric acid Cautiously pour 55 cm3 of concentrated (98% w/w) sulfuric acid into 500 cm 3 of deionised water with continuous stirring. Make the solution up to 1dm 3 with deionised water. Care: concentrated H 2SO4 is very corrosive 2 FA 3 100 cm3 Na2CO3 + NaOH Dissolve 6.9g Na2CO3 in 1 dm 3 of deionised water. Concentration of Na2CO3 = 0.0865 mol dm–3 Dissolve 2.2 g of NaOH in 1 dm3 of solution. Concentration of NaOH = 0.0550 mol dm–3 FA 4 150 cm3 HCl Dilute 75 cm3 of 2.0 mol dm −3 HCl to 1 dm3 with deionised water. Concentration = 0.150 mol dm–3 Methyl orange - Methyl orange - Thymol Blue - Thymol Blue - 3 FA 6 15 cm3 0.100 mol dm−3 Fe(NO3)3•9H2O + 0.200 mol dm−3 Zn(NO3)2•6H2O Dissolve 40.4 g of hydrated iron(III) nitrate, Fe(NO3)3.9H2O in each dm3 of solution. Dissolve 59.5 g of hydrated zinc nitrate, Zn(NO3)3 in each dm3 of solution. KI 5 cm3 0.100 mol dm–3 potassium iodide, KI Dissolve 16.6 g KI in deionised water and make up to 1 dm3 with deionised water. Starch Solution 5 cm3 Starch Solution Add 20 g slowly to 500 cm3 of boiling deionised water with stirring. Stir until a clear solution is obtained and make up to 1 dm3 using hot deionised water. Cool the solution before dispensing. Zn granule 1 Zn Granule

List of Apparatus and Chemicals for 2025 Y6 Prelim Practical (1) 1 × 50 cm3 burette (2) 1 × 25 cm3 pipette (3) 1 x 250 cm3 glass beaker (4) 2 × 250 cm3 conical flask (5) 2 × 100 cm3 measuring cylinder (6) 1 x glass rod (7) 1 × thermometer (0.2 °C division) (8) 3 × Styrofoam cup (9) 2 × filter funnel (10) 1 × pipette filler (11) 1 × retort stand and clamp (12) 1 × white tile (13) 1 × deionised water bottle (14) 4 × teat pipette (15) 4 × test tube (16) 1 × test tube rack (17) 1 × test tube holder (18) 1 × lighter (19) 1 × delivery tube (fitted to test tube) (20) 1 x spatula (21) 1 × brush set (for cleaning test-tubes and boiling tubes) (22) Wooden splint (23) Filter paper (24) Red and blue litmus paper (25) UI paper and colour chart (26) 1 × safety goggles (27) Starch solution (28) Zn granule (29) Thymol Blue indicator (30) Methyl Orange indicator Chemicals: FA 1, FA 2, FA 3, FA 4, FA 6