2023 PRSS Chem Prelims P1

Name Class Register Number SECONDARY 4 EXPRESS PRELIMINARY EXAMINATION 2023 CHEMISTRY Paper 1 Multiple Choice Friday 1105 – 1205 6092/01 25 Aug 2023 1 hour Additional Material: 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 on the Answer Sheet in the spaces 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 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 14. The use of an approved scientific calculator is expected, where appropriate. This document consists of 14 printed pages, including the cover page. Setter: Ms Chua Wei Tian [Turn over Pasir Ris Secondary School

PRSS_2023_S4E_PRELIM_CHEM_ 6092_P1 2 1 A mixture is separated using the apparatus shown. What is the likely identity of the mixture? A aqueous copper(II) sulfate and aqueous sodium chloride B aqueous copper(II) sulfate and calcium carbonate C copper and sulfur D ethanol and ethanoic acid 2 The formula of zinc oxide can be investigated by using the fact that when zinc is heated, it reacts with oxygen to form zinc oxide. Which apparatus is used for this investigation? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3 3 Which statement about states of matter is correct? A When a gas cools, the particles cannot vibrate about its fixed positions. B When a liquid freezes, it becomes a solid and energy is released to the surroundings. C When a solid is heated, the size of particles increases. D When a solid melts, the particles get further apart and have less energy.

PRSS_2023_S4E_PRELIM_CHEM_ 6092_P1 3 4 The melting points and boiling points of some gases in air are shown. gas melting point / °C boiling point / °C argon –190 –187 nitrogen –210 –197 oxygen –220 –183 At which temperature will oxygen be the only liquid present? A –180°C B –185°C C –188°C D –200°C 5 Deuterium, D, is an isotope of hydrogen with a nucleon number of 2. Heavy water, D2O, is water in which both the hydrogen atoms have been replaced with deuterium. It is commonly used in nuclear reactors. Some properties of ordinary water and heavy water are as shown. ordinary water, H2O heavy water, D2O relative molecular mass 18 20 melting point / ºC 0 3.8 boiling point / ºC 100.0 101.4 density / g/cm3 0.997 1.104 Which process can be used to recover heavy water from ordinary water? A cracking B fractional distillation C separating funnel D simple distillation 6 The diagrams below can be used to illustrate the following. 1 pure element 2 a mixture of elements 3 pure compound 4 a mixture of elements and a compound W X Y Z What is the correct order of the diagrams? 1 2 3 4 A W X Y Z B Z W X Y C W Y X Z D X Z W Y

PRSS_2023_S4E_PRELIM_CHEM_ 6092_P1 4 7 An element, M, has p protons and n neutrons in its nucleus. Which row gives the correct number of protons, neutrons and electrons in a positive ion of an isotope of M? protons neutrons electrons A p n p + 1 B p n – 1 p – 1 C p + 1 n p + 1 D p + 1 n + 1 p – 1 8 The atomic structures of two elements, Q and R, are shown. What is the mass of one mole of the compound formed between Q and R? A 18 g B 25 g C 32 g D 43 g 9 In which molecule are all the valence electrons of the atoms involved in bonding? A CH4 B HF C H2O D NH3 10 J, K and L are three different elements in the Periodic Table. The electronic structure of the compound formed between J, K and L, with only the valence electrons, is shown. Which statement is incorrect? A Element J belongs to Group II of the Periodic Table. B Element K could be nitrogen. C Element K and element L are bonded together by a covalent bond. D Element L is a metal.

PRSS_2023_S4E_PRELIM_CHEM_ 6092_P1 5 11 Five solutions were prepared so that each solution contained 1 mol/dm3 of one of the following ions: Fe2+, Fe3+, Na+, Zn2+ and Cu2+. To each solution, excess aqueous ammonia was added and the precipitate, if any, was filtered and weighed. The masses were obtained and plotted on a bar graph. Which of the following shows the correct graph? 12 A concentrated aqueous solution of a strong acid, HX, contains molecules of water and the ions H+ and X–. Which statement is correct? A The pH value of the acid is above 7. B The solution also contains a high concentration of water molecules. C The solution also contains OH– ions. D The solution contains less H+ ions than water molecules. 13 Two reagent bottles contain solutions of ammonium nitrate and ammonium carbonate respectively. The labels have fallen off the bottles. Which substance could be added to each bottle to identify the reagents correctly? A aqueous ammonia B aqueous nitric acid C aqueous potassium nitrate D aqueous sodium hydroxide

PRSS_2023_S4E_PRELIM_CHEM_ 6092_P1 6 14 Z is a solid which conducts electricity and has a high melting point. On warming, Z partly dissolves in excess dilute nitric acid, leaving behind a residue. What is the likely identity of Z? A brass B graphite C sodium chloride D zinc 15 Which three salts are all prepared by precipitation? A barium sulfate, calcium nitrate, lead(II) sulfate B barium sulfate, calcium nitrate, silver chloride C calcium carbonate, barium sulfate, lead(II) chloride D calcium chloride, barium sulfate, silver sulfate 16 In an experiment, 2.0 cm3 of 1.0 mol/dm3 aqueous copper(II) nitrate and 4.0 cm3 of 1.0 mol/dm3 aqueous potassium carbonate are mixed. What does the reaction vessel contain once the reaction is complete? A a colourless solution only B a green precipitate and a blue solution C a green precipitate and a colourless solution D a white precipitate and a colourless solution 17 Ammonia is used to make nitric acid, HNO3 by the Ostwald Process. Three reactions occur in the following stages. 1 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) 2 2NO(g) + O2(g) → 2NO2(g) 3 3NO2(g) + H2O(l) → 2HNO3(aq) + NO(g) What is the number of moles of nitric acid produced from the reaction between 50.0 dm3 of oxygen gas and excess ammonia gas in stage 1? A 1.11 B 1.25 C 1.39 D 1.74 18 Hydrazine, N2H4, is a powerful reducing agent. When reacted with an aqueous solution containing silver ions, nitrogen is one of the products formed. Which ionic equation best represents this reaction? A N2H4 + 2Ag+ → N2 + 2AgH2 B N2H4 + Ag+ → N2 + 2H2 + Ag C N2H4 + Ag+ → N2 + 4H+ + Ag D N2H4 + 4Ag+ → N2 + 4H+ + 4Ag

PRSS_2023_S4E_PRELIM_CHEM_ 6092_P1 7 19 Dilute ethanoic acid was titrated with aqueous sodium hydroxide. The pH changes were recorded using a pH meter. The graph of pH against volume of alkali added was plotted as shown. The diagram shows the pH ranges of three indicators. Which indicator(s) can be used to determine the end-point of the titration? A methyl orange only B phenolphthalein only C bromothymol blue and phenolphthalein only D bromothymol blue, methyl orange and phenolpthalein 20 Some properties of metal H are listed. • H does not react with cold water. • H reacts with dilute hydrochloric acid. • No reaction occurs when the oxide of H is heated with carbon. What is a possible identity of metal H? A copper B iron C magnesium D potassium

PRSS_2023_S4E_PRELIM_CHEM_ 6092_P1 8 21 10 cm3 of propane is burned in 70 cm3 of oxygen in a closed contain