NJC 2024 H2 Timed Practice 2 Paper

1 NJC SH2 Timed Practice 9729/01/24 [Turn over NATIONAL JUNIOR COLLEGE SH2 TIMED PRACTICE Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Optical Answer Sheet Data Booklet 9729/01 27 June 2024 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. 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: 2305648 35648 This document consists of 12 printed pages.

2 NJC SH2 Timed Practice 9729/01/24 1 Which statement about one mole of a metal is always correct? A It contains the same number of atoms as 0.5 mol of hydrogen gas. B It contains the same number of atoms as 1 12 mol of 12C. C It has the same mass as 1 mol of hydrogen atoms. D It can be oxidized by a reaction with an acid. 2 10 cm3 of a gaseous hydrocarbon was reacted with an excess of oxygen. A contraction of 30 cm3 occurred. On treating the cooled resulting mixture with excess barium hydroxide, a further contraction of 40 cm3 occurred. All volumes were measured at room temperature and pressure. What is the formula of the hydrocarbon? A C2H4 B C2H6 C C4H8 D C4H10 3 The following reaction occurs when chlorine is added to water. Cl2(g) + H2O(l) HOCl(aq) + HCl(aq) Which statement about this reaction is correct? A Chlorine is both oxidised and reduced. B Chlorine is oxidised but not reduced. C Hydrgen is both oxidised and reduced. D Hydrogen is oxidised but not reduced.

3 NJC SH2 Timed Practice 9729/01/24 [Turn over 4 X is either nitrogen or sulfur and forms pollutant oxide Y in a car engine. Further oxidation of Y to Z occurs in the atmosphere. In this further oxidation, 1 mol of Y reacts with 0.5 mol of gaseous oxygen molecules. Which statements about X, Y and Z can be correct? 1 The oxidation number of X increases by two from Y to Z. 2 Y has an unpaired electron in its molecules. 3 Y is a polar molecule. A 1 only B 1 and 2 C 2 and 3 D 1, 2 and 3 6 Histidine is an amino acid. Histidine What are the approximate bond angles 1, 2 and 3? 1 2 3 A 109.5° 107° 90° B 120° 107° 109.5° C 120° 120° 90° D 120° 120° 109.5°

4 NJC SH2 Timed Practice 9729/01/24 7 Ammonium ions, NH4+, are formed when ammonia gas reacts with hydrogen chloride gas. Which statement about the changes that occurs in this reaction is correct? A The dipole moment of an ammonium ion is greater than the dipole moment of an ammonia molecule. B The H−N−H bond angle decreases when an ammonium ion is formed. C The hybridisation of nitrogen does not change. D There is electron transfer from nitrogen to chlorine. 8 Ethylene glycol, HOCH 2CH2OH, is used as a de -icer. It allows ice to melt at temperatures below 0 °C. Which statements are correct? 1 Ethylene glycol changes the extensive network of hydrogen bonds in ice. 2 Ethylene glycol molecules form hydrogen bonds with other ethylene glycol molecules. 3 Ethylene glycol molecules will dissolve in the water formed from the ice. A 1 only B 1 and 2 C 2 and 3 D 1, 2 and 3 9 When an evacuated tube of volume 400 cm 3 is filled with gas at 300 K and 101 kPa, the mass of the tube increases by 0.65 g. Assume the gas behaves as an ideal gas. What is the identity of the gas? A Argon B Helium C Krypton D Neon

5 NJC SH2 Timed Practice 9729/01/24 [Turn over 10 Two identical bulbs at the same temperature contain ideal gases A and B separately. The density of gas A is twice that of gas B and the molecular mass of gas A is half that of gas B. What is the ratio of the pressure of gas A to that of gas B? A 1 : 2 B 1 : 1 C 2 : 1 D 4 : 1 11 When 60 cm3 of 1 mol dm-3 of sulfuric acid and 40 cm3 of 2 mol dm-3 sodium hydroxide were mixed in a styrofoam cup, the temperature rose by 6.5 C. Calculate the standard enthalpy change of neutralisation in kJ mol −1. Assume that the specific heat capacity of the solution is 4.18 J g-1 K-1. A −22.6 B −34.0 C −45.3 D −57.0 12 Nitric acid is made industrially by the oxidation of ammonia. The overall equation for the process is shown. equation 1: NH3(g) + 2O2(g) → HNO3(aq) + H2O(l) The process happens in three stages. The equations and enthalpy changes for these stages are given. Stage 1: 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(l) ∆H = −904 kJ mol-1 Stage 2: 2NO(g) + O2(g) → 2NO2(g) ∆H = −114 kJ mol-1 Stage 3: 4NO2(g) + O2(g) + 2H2O(l) → 4HNO3(aq) ∆H = −348 kJ mol-1 What is the enthalpy change of the process shown in equation 1? A −1480 kJ mol-1 B −370 kJ mol-1 C −341.5 kJ mol-1 D +82.0 kJ mol-1

6 NJC SH2 Timed Practice 9729/01/24 13 Hydrogen can be made from steam according to the following equation: H2O(g) + C(s) → H2(g) + CO(g) The Gibbs free energy change of reaction at two different temperatures are shown ∆G1 = +78 kJ mol−1 at 378 K ∆G2 = −58 kJ mol−1 at 1300 K Which row of the table gives the correct sign of ∆H and ∆S for this reaction? H S A − − B − + C + − D + + 14 A student carried out two experiments using MnO 2 as a catalyst to decompose hydrogen peroxide. The equation for this reaction is shown. 2H2O2(aq) → 2H2O(l) + O2(g) The student’s results are recorded in the table. Experiment Mass of MnO2 Conditions Vol of H2O2 Final vol of O2 Time taken 1 0.25 g r.t.p 10.0 cm3 48 cm3 200 s 2 0.25 g r.t.p 10.0 cm3 48 cm3 500 s Which statements are correct? 1 The activation energy was the same for both experiments. 2 The concentration of the hydrogen peroxide solution used was 0.4 mol dm-3. 3 The MnO 2 used in experiment 1 was in a larger piece than the MnO 2 used in experiment 2. A 1 only B 1 and 2 C 2 and 3 D 1, 2 and 3

7 NJC SH2 Timed Practice 9729/01/24 [Turn over 15 When an equimolar mixture of H 2 and I2 react, the mole fraction of H I in the final mixture is x at 500 C H2(g) + I2(g) 2HI(g) What is the equilibrium constant, Kp, for the reaction at 500 C? A 𝑥2 (1−𝑥)2 B 𝑥2 (1−2𝑥)2 C 4𝑥2 (1−𝑥)2 D 4𝑥2 (1−2𝑥)2 16 The graph below shows how the percentage of product present at equilibrium varies with temperature and pressure for a reaction. A 4Fe (s) + 3O2 (g) 2Fe2O3 (s) ∆H = −1644 kJ mol−1 B 2C (s) + O2 (g) 2CO (g) ∆H = −222 kJ mol−1 C N2O4(g) 2NO2(g) ∆H = +57 kJ mol−1 D CO(g) + Cl2(g) COCl2(s)