2023 CCHS(M) Chem Prelims P1

[Turn over Name: Class: Class Register Number: Parent’s Signature ______________________ PRELIMINARY EXAMINATION 2023 SECONDARY 4 CHEMISTRY 6092/01 Paper 1 Multiple Choice September 2023 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and register number clearly in the spaces provided at the top of this page. 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 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. A copy of the Periodic Table is printed on page 18. The use of an approved scientific calculator is expected, where appropriate. This document consists of 18 printed pages.

2 2023 Preliminary Exam/CCHMS/Secondary 4/Chemistry/6092/01 1 A student accidentally mixed 50 cm3 of oil and 5 g of solid calcium nitrate. Which sequence of separation would allow him to obtain pure samples of oil and solid calcium nitrate most easily? A Filtration followed by washing the residue with water. B Add water with stirring, use a separating funnel followed by crystallisation. C Simple distillation followed by crystallisation. D Use a separating funnel, chromatography followed by crystallisation. 2 The rate of diffusion of nitrogen and ammonia gases were compared at 50 oC and 25 oC. Which would have the slowest rate of diffusion? A Nitrogen gas at 50 oC. B Nitrogen gas at 25 oC. C Ammonia gas at 50 oC. D Ammonia gas at 25 oC. 3 An aqueous solution containing two salts is found. A series of tests is carried out to identify the ions present. The results are shown. test observations Add dilute nitric acid followed by aqueous lead(II) nitrate. No effervescence and white precipitate is observed. Add aqueous sodium hydroxide followed by warming. White precipitate is formed and dissolves in excess sodium hydroxide to form a colourless solution. No effervescence is observed. Add aluminium foil followed by warming. Effervescence is observed and gas turns moist red litmus paper blue. Add aqueous ammonia. White precipitate is formed. The mass of the white precipitate decreases by half when excess ammonia is added. Which of the following salts are present in the aqueous solution? A zinc sulfate and aluminium nitrate B zinc sulfate and calcium nitrate C ammonium chloride and aluminium sulfate D calcium chloride and ammonium sulfate

3 [Turn over 2023 Preliminary Exam/CCHMS/Secondary 4/Chemistry/6092/01 4 Three particles and their nuclide notations are shown. Particle 1 2 3 Nuclide notation X Y Z Which of the following statements is correct about the particles? A Particle 1 and 2 have the same number of neutrons. B Particle 1 and 3 have the same number of electrons. C Particle 2 has fewer neutrons than particle 3. D Particle 1 has more electrons than particle 3. 5 In which of the following substances are the particles farthest from one another at 25 oC? A dilute hydrochloric acid B iron(II) oxide C bromine D methane 19 39 40 19 + 16 34 2 –

4 2023 Preliminary Exam/CCHMS/Secondary 4/Chemistry/6092/01 6 The structural formulae of boron oxide and asparagine are shown. What is the total number of outer electrons not involved in bonding in boron oxide and asparagine? boron oxide asparagine A 12 12 B 12 16 C 14 12 D 14 16 7 The table below gives the number of subatomic particles of element X and Y. subatomic particles X Y protons 17 11 neutrons 20 12 Which diagram best represents the structure of the substance formed by X and Y? A B C D

5 [Turn over 2023 Preliminary Exam/CCHMS/Secondary 4/Chemistry/6092/01 8 Three elements W, X, Y, and Z have consecutive, increasing proton (atomic) numbers. Element Y exists as a colourless, monatomic gas at room temperature. Which will be the chemical formula of a compound formed between W and chlorine? A WCl B W2Cl C WCl2 D W2Cl3 9 Compound G contains two elements, metal R and non-metal Q. G consists of a lattice of positive ions and negative ions. Each positive ion is surrounded by four negative ions and each negative ion is surround by eight positive ions. Which ions are present in, and what is the formula of, compound G? ions present formula A R+ Q2– R2Q B R2+ Q– RQ2 C Q+ R2– Q2R D Q2+ R– QR2 10 Silver, graphite, silver nitrate and sulfur dioxide show different physical properties. Which statement is correct? A Silver and silver nitrate can conduct electricity in water due to their free moving ions. B Silver has high melting point due to the strong electrostatic forces of attraction between oppositely charged ions in its structure. C Graphite can conduct electricity within each layer in its structure due to free moving electrons. D Sulfur dioxide has a low boiling point as weak forces of attraction between its atoms are overcome during boiling.

6 2023 Preliminary Exam/CCHMS/Secondary 4/Chemistry/6092/01 11 Hydrogen gas reacts with chlorine gas to form hydrogen chloride gas. H2(g) + Cl2(g) ® 2HCl(g) What is the final volume of the gas mixture when 20 dm3 of hydrogen is reacted with 30 dm3 of chlorine gas at 100 °C? A 40 dm3 B 50 dm3 C 60 dm3 D 70 dm3 12 8 g of X2O3, an oxide of element X, contains 70 % of X. How many moles of X does 8 g X2O3 contain? A 8 3 16 2 B 8 2 16 3 C 2.4 3 16 2 D 2.4 2 16 3 13 On heating, ammonium nitrate, NH4NO3, decomposes to form dinitrogen oxide and water. NH4NO3 → N2O + 2H2O When 80 g of an impure sample of ammonium nitrate is heated, 27 g of water are formed. What is the mass of ammonium nitrate in the impure sample? [Ar: H, 1; O, 16; N, 14] A 20.0 g B 49.5 g C 60.0 g D 120 g x x x x

7 [Turn over 2023 Preliminary Exam/CCHMS/Secondary 4/Chemistry/6092/01 14 Ammonia and excess carbon dioxide can react to form urea and water in a reaction. 2NH3 + CO2 → CON2H4 + H2O The percentage yield of this reaction is 80 %. What is the mass of ammonia required for this reaction to obtain 60.0 g of urea? [Mr: NH3, 17; CO2, 44; CON2H4, 60; H2O, 18] A 10.6 g B 27.2 g C 34.0 g D 42.5 g 15 In the diagram below, each cell contains an aqueous solution of a single salt and all the four electrodes are platinum. Electrode Q and S increase in mass during the electrolysis and no gas is given off at Q or S. If the increase in mass of Q is greater than the increase in mass of S at the same time, which one of the following statements is necessarily true? A The cation of the solution in cell 1 is different from the cation of the solution in cell 2. B The anion of the solution in cell 1 is different from the anion of the solution in cell 2. C The current flowing in cell 1 is greater than the current flowing in cell 2. D The loss in mass of electrode P is less than the loss in mass of electrode R. P Q aqueous solutions cell 1 cell 2 S R + –

8 2023 Preliminary Exam/CCHMS/Secondary 4/Chemistry/6092/01 16 The apparatus was set up as shown. For which pair of metals would effervescence be seen only at metal Y? metal X metal Y A copper zinc B iron copper C lead iron D iron zinc 17 The energy profile diagram of a reversible reaction is shown below. A + B C + D What is the value of the activation energy for the backward reaction? A 90 kJ/mol B 70 kJ/mol C 50 kJ/mol D 20 kJ/mol energy / kJ/mol progress of reaction A + B C +