CCHY Chem Prelim P1 P2 with ans

This document consists of 19 printed pages, INCLUDING the cover page. [Turn over 2024 Preliminary Examination Secondary Four Express CANDIDATE NAME CLASS INDEX NUMBER CHEMISTRY 6092/01 Paper 1 Multiple Choice 23 August 2024 Additional Materials: OTAS 1 hour READ THESE INSTRUCTIONS FIRST Write your name, class and index number in the spaces at the top of this page and on the OTAS provided. There are forty 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 OTAS. Read the instructions on the OTAS 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. A copy of the Periodic Table is printed on page 19. The use of an approved scientific calculator is expected, where appropriate. O CHUNG CHENG HIGH SCHOOL (YISHUN)

2 2024 CCHY Preliminary Examination Chemistry (6092/01) / Sec Four Express [Turn over 1 In a volumetric experiment involving the addition of hydrochloric acid to 25.0 cm 3 of aqueous sodium hydroxide, it is necessary to determine when the reaction is just complete. Which piece of apparatus could be used to determine the end -point of the reaction? A electronic balance B gas syringe C stopwatch D thermometer 2 Which diagram shows the arrangement of particles inside a balloon containing helium and oxygen? helium oxygen A B C D

3 2024 CCHY Preliminary Examination Chemistry (6092/01) / Sec Four Express [Turn over 3 A 50 cm3 sample of ethanol is mixed with 50 cm3 of water. The volume of the mixed ethanol and water is found to be 97 cm 3. Which statement is the best explanation? A Some volatile ethanol evaporate. B The ethanol molecules fit into gaps between water molecules. C Water and ethanol react to form a soluble salt. D Water and ethanol react to form a gas which escapes. 4 A beaker of nitrogen was inverted over a porous pot containing carbon monoxide as shown. The water level did not change. What is the reason for this? A Both gases are diatomic. B Nitrogen is an unreactive gas. C The two gases have the same molecular masses. D The gas particles are too large to pass through the porous pot. nitrogen carbon monoxide beaker porous pot water 50 cm3 of ethanol 50 cm3 of water

4 2024 CCHY Preliminary Examination Chemistry (6092/01) / Sec Four Express [Turn over 5 In an experiment to find the formula of magnesium oxide, magnesium metal is heated in a covered crucible. Why is the crucible covered? A to prevent air escaping from the crucible B to prevent magnesium carbonate forming C to prevent magnesium oxide escaping from the crucible D to prevent water vapour escaping from the crucible 6 The Rf values of some substances are shown below. The solvent used is ethanol. substance Rf value X 0.20 Y 0.80 Z 0.45 Which of the following cannot be concluded from the R f value of X? A Substance X is less soluble in ethanol than Y and Z. B Substance X will have the same Rf value when the solvent is changed to water. C The distance travelled by X is one-fifth the distance travelled by ethanol. D The distance travelled by Y is four times the distance travelled by X. 7 Bromine has a melting point of -2 oC and a boiling point of 59 oC. At which temperature is bromine a liquid? A B C D -50 -25 0 25 50 75 100 125 150

5 2024 CCHY Preliminary Examination Chemistry (6092/01) / Sec Four Express [Turn over 8 Which group of substances contain an element, a compound and a mixture? A copper, diamond, sand B dilute acid, brass, ethanol C glucose, ammonia, methane D graphite, polyethene, crude oil 9 In an experiment, a sample was vapourised, ionised and passed through an electric field. Analysis of the deflection occurring at the electric region revealed the following data for the sample. - source + What is the possible identify of the unknown particle X? A Br- B F- C Li+ D Rb+ 10 The relative atomic mass of naturally occurring chlorine is not a whole number. What is the reason for this? A Chlorine is unstable. B Chlorine atoms can have different number of neutrons. C Naturally occurring chlorine cannot be obtained pure. D The mass of the electron has been included. Na+ K+ X

6 2024 CCHY Preliminary Examination Chemistry (6092/01) / Sec Four Express [Turn over 11 What is the total number of electrons not involved in bonding in an ethyne, C 2H2, molecule? A 4 B 6 C 8 D 10 12 The formulae of four covalent molecules are shown. 1 H2O 2 CO2 3 CH3OH 4 CH3COOH In which pair of molecules does oxygen form at least one double bond in both molecules? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4 13 If one mole of a substance contains p number of particles, what is the number of gas molecules in a sample of 106.5 g of chlorine gas? A 0.5 p B 1.0 p C 1.5 p D 2.0 p 14 The diagram below shows the structures of the atoms of two elements. What is the relative molecular mass of the compound formed by these two elements? A 46 B 61 C 85 D 98

7 2024 CCHY Preliminary Examination Chemistry (6092/01) / Sec Four Express [Turn over 15 10 g of Z3O4 contains 7.5 g of Z. How many moles of Z does 7.5 g of the element contain? A 2.5 16 × 3 4 B 7.5 16 × 27 36 C 2.5 16 × 4 3 D 10 16 × 4 3 16 28 g of gaseous hydrocarbon X has a volume of 12 dm 3 at room temperature and pressure. What is the molecular formula of X? A C2H4 B C3H8 C C4H8 D C5H10 17 Potassium hydroxide reacts with dilute sulfuric acid to form potassium sulfate and water. 2KOH + H 2SO4 → K2SO4 + 2H2O 25 cm 3 of 2.5 mol / dm3 potassium hydroxide reacted with dilute sulfuric acid to give 0.05 mol of water. Which of the following volumes and concentrations of dilute sulfuric acid were used? A 25.0 cm3 of 2.0 mol / dm 3 B 20.0 cm3 of 2.5 mol / dm 3 C 12.5 cm3 of 2.0 mol / dm 3 D 15.0 cm3 of 2.5 mol / dm 3 18 On heating, ammonium nitrate, NH 4NO3, decomposes to form dinitrogen oxide and water. NH4NO3 → N2O + 2H 2O When 80 g of an impure sample of ammonium nitrate is heated, 27 g of water are formed. Which expression shows the number of grammes of ammonium nitrate in the impure sample? A 66 × 27 36 B 80 × 27 36 C 80 × 27 18 D 80 × 9 36

8 2024 CCHY Preliminary Examination Chemistry (6092/01) / Sec Four Express [Turn over 19 When a strong acid is neutralised by a strong base, the change in heat content is always the same (∆H = -57.6 kJ). This is so because A strong acids and strong bases have the same heat content. B strong acids and strong bases produces salt and water only. C strong acids and strong bases have equal strength. D the reaction involves only H+ and OH- ions to produce water. 20 The dissociation constant for an acid indicates the extent to which it dissociates into ions. The higher the dissociation constant, the stronger the acid. The dissociation constant for some acids is given below along with two possibly correct statements. acid dissociation constant methanoic acid 1.80 × 10−4 ethanoic acid 1.75 × 10−5 propanoic acid 1.34 × 10−5 bromoethanoic acid 1.30 × 10−3 statement 1: Increasing the length of the carbon chain makes the acid stronger. statement 2: Replacing a hydrogen by a bromine in ethanoic acid makes the