2025 YIJC H1 Chem Prelim P1 (for exchange)

©YIJC 8873/01/JC2/PE/2025 YISHUN INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 1 CANDIDATE NAME CG H1 GROUP 1 / 2 CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 8873/01 18 September 2025 1 hour READ THESE INSTRUCTIONS FIRST This document consists of 13 printed pages and 3 blank pages. Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name and class in the spaces at the top of this page and 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 booklet. The use of an approved scientific calculator is expected, where appropriate.

2 ©YIJC 8873/01/JC2/PE/2025 1 The table below contains incomplete information about three ions, E, F and G, which are isoelectronic (same number of electrons). The atoms of F and G are isotopes. ion mass number atomic number number of neutrons number of electrons charge E 55 25 y F 56 26 G x 31 3+ What are the possible values of x and y? x y A 56 2+ B 56 3+ C 57 2+ D 57 3+ 2 In two separate experiments, a beam of protons and a beam of electrons, travelling at the same velocity, pass through an electric field as shown. Which set of observations is correct? A The two beams are deflected in opposite directions. The electron beam is deflected the most. B The two beams are deflected in opposite directions. The proton beam is deflected the most. C The two beams are deflected in the same direction. The electron beam is deflected the most. D The two beams are deflected in the same direction. The proton beam is deflected the most. beam of particles + – source

©YIJC 8873/01/JC2/PE/2025 [Turn over 3 3 Use of the Data Booklet is relevant to this question. Which species has three unpaired electrons? A Al B Ti3+ C Zn2+ D Cr3+ 4 Use of the Data Booklet is relevant to this question. How many atoms are there in 100 cm3 of oxygen gas measured at s.t.p.? A 2.51  1021 B 2.65  1021 C 5.02  1021 D 5.30  1021 5 The relative atomic mass of antimony, which consists of the isotopes 121Sb and 123Sb, is 121.8. What is the percentage of 123Sb in the isotopic mixture? A 40% B 45% C 50% D 60% 6 The boiling point of ethylamine, CH3CH2NH2, is 16.6 °C. Which bonds are broken when ethylamine is boiled? 1 instantaneous dipole–induced dipole interactions 2 hydrogen bonds 3 covalent bonds A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only

4 ©YIJC 8873/01/JC2/PE/2025 7 Three substances, H, J and K, have physical properties as shown. substance H J K melting point / °C 801 –7 3550 boiling point / °C 1413 59 4827 electrical conductivity when in solid state poor poor good What could be the identities of H, J and K? H J K A bromine sodium chloride graphite B bromine sodium chloride silicon dioxide C sodium chloride bromine graphite D sodium chloride bromine silicon dioxide 8 The kinetics of a zero order reaction L → M was investigated. A pair of quantities was plotted and the following graph was obtained. Which pair of quantities gives the graph above? y-axis x-axis A rate [L] B rate [M] C [L] time D [M] time 0 y-axis x-axis

©YIJC 8873/01/JC2/PE/2025 [Turn over 5 9 There are 39 known isotopes of radon (Rn) from 193Rn to 241Rn. The most stable isotope is 222Rn with a half-life of 3.8 days. Given that the decay of 222Rn is a first order reaction , how long will it take for 222Rn to decrease to one-eighth of its original amount? A 7.6 days B 11.4 days C 15.2 days D 30.4 days 10 Which changes in conditions would result in a change in the value of the equilibrium constant, Kc, for the following reaction? N2(g) + 3H2(g) ⇌ 2NH3(g) ∆H = −92 kJ mol−1 1 increasing temperature 2 increasing the concentration of N2 3 adding a catalyst A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only 11 Ethanol in blood can be assumed to be in dynamic equilibrium with ethanol in breath. This equilibrium forms the basis of the roadside breathalyser test. C2H5OH (blood) ⇌ C2H5OH (breath) The equilibrium constant, Kc, for this equilibrium is 4.3 x 10−4. The concentration of ethanol in a motorist’s blood is found to be 75 mg in 100 cm3 of blood. What is the concentration of ethanol in the motorist’s breath in mg per 100 cm3? A 3.23  10−4 B 3.23  10−2 C 1.74  105 D 3.23  106

6 ©YIJC 8873/01/JC2/PE/2025 12 Hydrogen reacts with iodine to form hydrogen iodide . This reaction is reversible and is allowed to reach an equilibrium. H2(g) + I2(g) ⇌ 2HI(g) ∆H⦵ = +26.5 kJ mol−1 At time = t1, the temperature was increased. Which graph correctly shows the changes in the concentrations of hydrogen, iodine and hydrogen iodide? A B C D 13 Which statement best defines the term bond energy for HBr? A Energy released when one mole of HBr is formed from its gaseous atoms. B Energy released when one mole of HBr is formed from its gaseous ions. C Energy required when one molecule of HBr is broken down into its gaseous atoms. D Energy required when one mole of HBr is broken down into its gaseous atoms. concentration time t2 [HI] [H2] [I2] t1 concentration time t2 [HI] [H2] [I2] t1 concentration time t2 [HI] [H2] [I2] t1 concentration time t2 [HI] [H2] [I2] t1

©YIJC 8873/01/JC2/PE/2025 [Turn over 7 14 Which change could have the energy level diagram shown? A H2O(g) → H2O(l) B C(s) + O2(g) → CO2(g) C Li+(g) + H−(g) → LiH(s) D LiOH(s) → Li+(g) + OH−(g) 15 Use of the Data Booklet is relevant to this question. The lattice energies of rubidium fluoride, RbF, and caesium chloride, CsCl, are shown in the table. compound lattice energy / kJ mol–1 RbF −760 CsCl −650 Which value is likely to be the lattice energy of caesium fluoride, CsF, in kJ mol−1? A −460 B −550 C −680 D −800 energy reactants products

8 ©YIJC 8873/01/JC2/PE/2025 16 Sodium bicarbonate, NaHCO3, decomposes into sodium carbonate, water and carbon dioxide when heated. 2NaHCO3(s) → Na2CO3(s) + H2O(g) + CO2(g) ∆Hr = z kJ mol–1 The following enthalpy changes of formation are given. compound ∆Hf / kJ mol–1 NaHCO3(s) −948 Na2CO3(s) −1131 H2O(g) −286 CO2(g) −394 What is the value of z? A −85 B +85 C −863 D +863 17 What is the definition of an Arrhenius base? A A substance that accepts hydrogen ions. B A substance that donates a lone pair of electrons. C A substance that produces hydroxide ions in aqueous solution. D A substance that readily reacts with an acid to form a salt and water only. 18 The equation for the dissociation of water is as follows: 2H2O(l) ⇌ H3O+(aq) + OHꟷ(aq) ∆H = +57 kJ molꟷ1 Which statement about pure water is correct? A As the volume of water increases, the pH of water also increases. B As temperature increases, the pH of water also increases. C The sum of pH and pOH is 14 at all temperatures. D [H+] will always equal to [OHꟷ] at all temperatures.

©YIJC 8873/01/JC2/PE/2025 [Turn over 9 19