EJC Prelim H1 Chemistry Paper 1 QP

© EJC [Turn Over EUNOIA JUNIOR COLLEGE JC2 Preliminary Examination 2025 General Certificate of Education Advanced Level Higher 1 CHEMISTRY Paper 1 Multiple Choice 8873/01 19 September 2025 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, civics group 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. 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 question paper. The use of an approved scientific calculator is expected, where appropriate. This document consists of 14 printed pages and 2 blank pages.

2 © EJC 8873/01/J2PE/20 1 In which pair of atoms, in their ground states, have the same number of unpaired electrons? A B and Ca B F and Na C Ne and P D Be and Si 2 Three particles approach an electric field at the same speed. They are deflected as they pass through the electric field. What could be the identities of particles X, Y and Z? X Y Z A 35 17Cl– 37 17Cl– 23 11Na+ B 6 3Li+ 7 3Li+ 1 1H– C 37 17Cl– 35 17Cl– 23 11Na+ D 7 3Li+ 6 3Li+ 1 1H– 3 Which molecule has the largest bond angle? A BF3 B SiCl4 C H2S D PH3 + – X Y Z

3 © EJC 9729/01/J2PE/25 [Turn over 4 The boiling points of hydrogen chloride, HCl, and chlorine, Cl2 are shown in the table. boiling point / ºC HCl −85 Cl2 −34 Which pair of statements explain this difference? 1 The forces of attraction between C l2 molecules are instantaneous dipole- induced dipole attractions. 2 The force s of attraction between HC l molecules are permanent dipole - permanent dipole attractions. 3 H−Cl bonds are stronger than Cl−Cl bonds. 4 The forces of attraction between C l2 molecules are stronger because C l2 molecules have more electrons. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4 5 Which of the following molecule will not form a hydrogen bond with another of its own molecule? A CH3CHO B CH3NH2 C CH3OH D HF 6 Gases can be liquefied under certain conditions. Which statement best describes why a gas liquefies under high pressure? A Increasing the pressure causes the temperature of the gas to decrease to below its boiling point. B Increasing the pressure decreases the kinetic energy of the molecules, creating the ordered liquid state. C Increasing the pressure decreases the size of the molecules , and so the intermolecular forces of attraction become stronger. D Increasing the pressure pushes the molecules closer together, and so the intermolecular forces of attraction become stronger.

4 © EJC 8873/01/J2PE/20 7 The table shows the results of experiments in which the halogens X2, Y 2 and Z 2 were added to separate aqueous solutions containing X–, Y– and Z– ions. X– (aq) Y– (aq) Z– (aq) X2 no reaction no reaction no reaction Y2 X2 formed no reaction Z2 formed Z2 X2 formed no reaction no reaction Which set contains the ions X–, Y– and Z– in order of their decreasing strength as a reducing agent? strongest ⎯⎯⎯⎯⎯→ weakest A X– Y– Z– B X– Z– Y– C Y– Z– X– D Z– X– Y– 8 Which element forms a chloride in which both covalent bonding and dative bonding are present? A Mg B Al C Si D P

5 © EJC 9729/01/J2PE/25 [Turn over 9 Use of the Data Booklet is relevant to this question. The sketch below shows the variation of properties of Period 3 elements. Which option shows the correct label for the axes? y x 1 melting point nucleon number 2 electronegativity atomic number 3 atomic radius highest possible oxidation state A 2 only B 2 and 3 C 1 and 3 D 1, 2 and 3 10 Use of the Data Booklet is relevant to this question. A 5 g sample of a diatomic gas, Y2, was found to contain 3.76 × 1022 atoms. What is the relative molecular mass of the gas? A 40 B 80 C 120 D 160 y x

6 © EJC 8873/01/J2PE/20 11 Carbon disulfide vapour, CS2(g), burns in oxygen according to the following equation. CS2(g) + 4O2(g) → CO2(g) + 2SO3(g) A sample of 10 cm 3 of carbon disulfide was burned in 60 cm3 of oxygen. The residual gases were passed through sodium hydroxide. Assuming all measurements were made at the same temperature and pressure in which CS2 was in the gaseous state, what is the final volume of gases left? A 50 B 40 C 30 D 20 12 Shikimic acid is a naturally occurring compound found in the spice plant star anise, also known as Japanese flower shikimi. What is the percentage composition by mass of carbon in shikimic acid? A 48.3% B 48.5% C 49.7% D 50.0%

7 © EJC 9729/01/J2PE/25 [Turn over 13 Which reaction could represent the energy level diagram shown? A CO2(g) → C(g) + 2O(g) B Ca2+(g) + 2Br−(g) → CaBr2(s) C C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(l) D HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) 14 Use of the Data Booklet is relevant to this question. Hydrazine, N2H4, undergoes the following reaction. H2N–NH2(g) ⎯⎯⎯⎯⎯→ 2N(g) + 4H(g) What is the value of y? A 550 B 1720 C 1970 D 2550 reactants products energy y kJ mol–1

8 © EJC 8873/01/J2PE/20 Use the following information to answer Q15 and Q16. Hydrogen peroxide slowly decomposes at room temperature. H2O2(aq) → H2O(l) + 1 2 O2(g) A series of experiments were carried out to study the energetics and kinetics of this reaction. 15 50 cm3 of 0.500 mol dm−3 aqueous hydrogen peroxide were placed in a polystyrene cup and its temperature was determined to be 23.0 ºC. 10 cm 3 of 0.500 mol dm −3 iron(III) nitrate, Fe(NO3)3, solution was added to catalyse the reaction. The mixture was stirred with a thermometer and a maximum temperature of 32.2 ºC was recorded. What is the enthalpy change of the reaction? A −77 kJ mol−1 B −92 kJ mol−1 C −96 kJ mol−1 D −323 kJ mol−1

9 © EJC 9729/01/J2PE/25 [Turn over 16 Two further experiments were performed to study the effects of adding lead(IV) oxide on the decomposition of hydrogen peroxide at constant temperature. Experiment 1 : 20 cm3 of H2O2 Experiment 2 : 20 cm3 of H2O2 and 1.0 g of lead(IV) oxide At the end of experiment 2, the mixture was filtered and 1.0 g of lead( IV) oxide was recovered. The results of the experiments are as shown. Which row is correct? value of rate constant activation energy A equal in experiment 1 and 2 higher in experiment 1 B equal in experiment 1 and 2 higher in experiment 2 C higher in experiment 2 higher in experiment 1 D higher in experiment 2 higher in experiment 2 17 If the reaction Q + R → S + T is described as zero order with respect to Q, which of the following statements correctly describes Q? A Q is a limiting reagent. B The rate of reaction is independent of [Q]. C The concentration of Q does not change during the reaction. D All of molecules Q do not possess energy sufficient to overcome the activation energy of the reaction. Volume of O2(g) / cm3 experiment 2 experiment 1 time / s 0 0

10 © EJC 8873/01/J2PE/20 18 Methane, CH4, is manufactured industrially by the catalytic reaction shown below. CO2(g) + 4H2(g)  CH4(g) + 2H2O(g) H = –165 kJ mol–1 The operating conditions are: 350 ºC; a pressure between 25 and 35 bar; a nickel catalyst. Which factor influences the choice of these conditions? A The catalyst increases the equilibrium yield of methane. B At high