NJC 2026 Prelim P1 QP

NATIONAL JUNIOR COLLEGE SH2 PRELIMINARY EXAMINATIONS Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Optical Answer Sheet Data Booklet 9476/01 17 Sept 2026 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, subject class and registration number on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. hou Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. Instructions on how to fill in the Optical Mark Sheet Shade the index number in a 5 digit format on the optical mark sheet: 2nd digit and the last 4 digits of the Registration Number. Example: Student Examples of Registration No. Shade: 2505648 55648 This document consists of 20 printed pages (including 3 blank pages).

2 NJC SH2 Prelim 9476/1/26 3 A mixture of the three gases, oxygen, nitrogen and argon, is at a total pressure of 500 kPa. There is a total of 1.2 moles of gases in the mixture. If the oxygen gas alone occupied the entire volume of the mixture, it would exert a pressure of 150 kPa. At room conditions, the amount of nitrogen gas in the mixture would occupy a volume of 5.76 dm3. Using the data from above, what is the partial pressure of the argon gas in the mixture? A 150 kPa B 200 kPa C 250 kPa D 300 kPa 1 The relative abundances of the isotopes of a sample of titanium are shown in the table below. relative isotopic mass 46 47 48 49 50 relative abundance 11.2 10.1 100.0 7.3 7.0 What is the relative atomic mass of titanium in this sample? A 47.89 B 47.90 C 47.92 D 48.00 2 A sample of pure gas is put into a gas syringe at 27.0 C and 16 kPa. The plunger of the syringe is pushed in to compress the gas, until the volume occupied is halved. After compression, the pressure of the gas is 40 kPa. What is the new temperature of the gas? A 33.8 C B 67.5 C C 102.0 C D 375.0 C

3 NJC SH2 Prelim 9476/1/26 [Turn over 4 The following graphs were obtained for three gases for the variation of pV with p, where p is the pressure and V is the volume of the gas. Which row is correct if gas M is HCl at 300 K? gas N temperature / K A HCl 400 B CH4 400 C O2 300 D HF 300 5 Which element has the same number of electron pairs and unpaired electrons in its valence shell? A beryllium B carbon C nitrogen D oxygen pV p Ideal gas Gas M Gas N

4 NJC SH2 Prelim 9476/1/26 6 The table identifies the shape and polarity of four molecules. Which row is correct? molecule molecular shape polarity A BrF3 trigonal planar polar B PCl3 trigonal pyramidal polar C SCl2 linear non-polar D CHF3 tetrahedral non-polar 7 Which option about the structure below is correct? Cl O N number of sp hybridised C number of sp2 hybridised C number of sp3 hybridised C A 1 3 8 B 1 3 6 C 0 4 8 D 0 4 6 8 Which pair of elements have bonds of the same type between their atoms in their standard states? A aluminium and phosphorus B chlorine and argon C magnesium and silicon D sulfur and chlorine

5 NJC SH2 Prelim 9476/1/26 [Turn over 9 When 25 cm3 of 1.0 mol dm–3 sodium hydroxide was neutralised with an equal volume of 0.5 mol dm–3 sulfuric acid, the temperature of the mixture rose by 7.0 C. What would be the temperature change if 50 cm 3 of 0.5 mol dm –3 sodium hydroxide is neutralised with an equal volume of 0.25 mol dm–3 sulfuric acid? Assume negligible heat loss in each case. A 14.0 C B 7.0 C C 3.5 C D 1.8 C 10 Which graph corresponds to the combustion of liquid ethanedioic acid, (COOH) 2 at increasing temperature (before the boiling point of water)? (COOH)2(l) + ½ O2(g) → 2CO2(g) + H2O(l) A B C D

6 NJC SH2 Prelim 9476/1/26 11 Which statements about the thermodynamic properties of the following reaction are correct? CaCO3(s) → CaO(s) + CO2(g) 1 The reaction is endothermic. 2 The entropy change for this reaction is positive. 3 The reaction becomes more feasible at higher temperatures. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only 12 Which suggested mechanism is consistent with the experimentally determined rate equation? rate equation suggested mechanism A rate = k [ICl] [H2] Step 1: 2 ICl k1 k−1 I2Cl2 (fast) Step 2: I2Cl2 + H2 k2 → I2 + 2HCl (slow) B rate = k [NO]2 [H2] Step 1: NO + H2 k1 k−1 N + H2O (fast) Step 2: N + NO k2 → N2O (slow) Step 3: N2O + H2 k3 → N2 + H2O (fast) C rate = k [S2O82–] [I–] Step 1: S2O82− + I− k1 k−1 [IS2O8]3− (fast) Step 2: [IS2O8]3− k2 → 2SO42− + I+ (slow) Step 3: I+ + I− k3 → I2 (fast) D rate = k [NO2]2 Step 1: NO2 + CO k1 k−1 NO2CO (fast) Step 2: NO2CO + NO k2 → 2NO + CO2 (slow)

7 NJC SH2 Prelim 9476/1/26 [Turn over 13 At elevated temperatures, gaseous sulfuryl chloride, SO 2Cl2, undergoes thermal decomposition into sulfur dioxide and chlorine gas. To determine the order of reaction, the rate of reaction was measured using different concentrations of SO2Cl2 in a sealed, rigid container at a constant temperature of 320 C. The results are given in the table below. experiment initial [SO2Cl2] / mol dm–3 initial rate / mol dm–3 min–1 1 0.215 2.84 × 10–3 2 0.333 4.40 × 10–3 Which statements are correct about the thermal decomposition of SO2Cl2? 1 The reaction is first order with respect to SO2Cl2. 2 The half-life of the reaction is 52.5 minutes. 3 The concentration of SO 2Cl2 remaining after exactly 105 minutes from experiment 2 is 0.0833 mol dm–3. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 14 Cobalt forms many coloured complexes with ligands such as H2O and SCN–. A 100 cm3 solution of Co2+(aq) turns from pink to bright blue when 10 cm 3 of NaSCN(aq) is added to the solution. [Co(H2O)6]2+(aq) + 4SCN‒ (aq) [Co(SCN)4]2‒ (aq) + 6H2O(l) pale pink bright blue At equilibrium, [Co(H 2O)6]2+ and [Co(SCN) 4]2‒ are found to be present in a mole ratio of 1:10. Given that lg(Kc) for the equilibrium is 3.00, which statement is incorrect? A At equilibrium, [SCN– ] = 3.16 × 10–1 mol dm–3. B The forward reaction is spontaneous. C The units of Kc is mol–4 dm12. D Dilution of the reaction mixture causes the position of equilibrium to shift left as the concentration of water increases.

8 NJC SH2 Prelim 9476/1/26 15 Deuterium, D12 is an isotope of hydrogen, H11 . Deuterium oxide, D 2O, is known as ‘heavy water’ and undergoes self-ionization similar to normal water as follows: 2D2O(l) D3O+(aq) + OD‒ (aq) Kd = 1.35 × 10‒15 mol2 dm‒6 at 25 C For D2O, the terms Kd is used instead of Kw and pD instead of pH.