2023 TKGS Chem Prelims P1

This document consists of 19 printed pages. TANJONG KATONG GIRLS’ SCHOOL PRELIMINARY EXAMINATION SECONDARY FOUR EXPRESS CANDIDATE NAME CLASS E INDEX NUMBER CHEMISTRY 6092/01 Paper 1 Multiple Choice 21 August 2023 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Write your name, index number on the Answer Sheet. There are forty questions in 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 19. The use of an approved scientific calculator is expected, where appropriate. Setter: Dr S Munira Marker: Dr S Munira

2 Tanjong Katong Girls’ School Sec 4 Preliminary Examination 2023 1 The diagram shows an experimental setup for the preparation and collection of a dry gas. What could the gas be? A ammonia B carbon dioxide C hydrogen D chlorine 2 The diagram shows how molecules in car exhaust gases diffuse into the air. Which statement describes what happens to these molecules next? A The molecules sink closer to the ground because they are heavier than air molecules. B The molecules move back together as they cool. C The molecules spread further into the air. D The molecules stay suspended where they are. molecules in air molecules in exhaust gases

Tanjong Katong Girls’ School Sec 4 Preliminary Examination 2023 3 When 50 cm3 of pure ethanol is mixed with 50 cm3 of pure water in a measuring cylinder, the mixture is immediately found to have a volume of about 97 cm3. What is the best explanation for this observation? A A small volume of the ethanol has evaporated. B The water molecules move into empty spaces between the ethanol molecules. C The ethanol molecules have a random arrangement in water. D Water and ethanol react together to form a compound. 4 The diagram shows a setup to distil a mixture of propanol (boiling point 88 oC) and heptane (boiling point 98 oC). Which graph correctly shows the changes in volume of distillate in the conical flask as the distillation proceeds? water out water in boiling flask mixture of liquids heat Temperature/ oC Temperature/ oC Temperature/ oC Temperature/ oC Volume of distillate Volume of distillate Volume of distillate Volume of distillate A B C D

Tanjong Katong Girls’ School Sec 4 Preliminary Examination 2023 5 Camphor is a substance used in skin ointments. A natural sample of camphor is found to contain impurities like iron(III) oxide, iron and sodium chloride. The table shows the effects of these substances with three different types of liquids. Which is the best method to obtain pure camphor? A Add ethanol, filter, rinse and dry. B Add dilute nitric acid, filter and crystallise. C Add dilute nitric acid, filter, rinse and dry. D Add water, filter, rinse and dry. 6 A beam of particles containing electrons is passed through charged plates. Which path shows how the electrons move through the plates? 7 A giant molecule is made up of a large number of carbon atoms, mainly isotopes carbon-12 and carbon-13. It was found that the relative atomic mass of carbon in the molecule is 12.2. What is the ratio by mass of carbon-12 to carbon-13? A 4 : 1 B 1 : 4 C 3 : 4 D 3 : 1 substance water ethanol dilute nitric acid camphor no effect dissolves no effect iron iron(III) oxide sodium oxide no effect no effect dissolves no effect no effect no effect reacts to give solution reacts to give solution dissolves positive plate negative plate A B C D

Tanjong Katong Girls’ School Sec 4 Preliminary Examination 2023 8 Chlorine gas, Cl2, at 40 oC diffuses more slowly than neon, Ne, at 20 oC. Which statement correctly explains the difference in diffusion rate of Cl2 and Ne? A Chlorine has a relative molecular mass of 71 whilst neon has a relative atomic mass of 20. B Chlorine is at a higher temperature than neon. C Chlorine is diatomic, and neon is monatomic. D Chlorine is more reactive than neon. 9 The structural diagrams of two molecules, X2Y and ZY2, are shown. X2Y ZY2 Which diagram represents a molecule of a compound formed between X and Z?

Tanjong Katong Girls’ School Sec 4 Preliminary Examination 2023 10 A student recorded four statements about elements, compounds and mixtures. 1 Elements and compounds have fixed melting points. 2 The properties of a compound are similar to that of its elements. 3 A mixture can be separated into its components by physical means. 4 Elements can exist either in the form of atoms or molecules. How many of the above statement(s) is/are incorrect? A one B two C three D four 11 The table shows information about particles X and Y. number of protons number of neutrons electronic structure X Y 9 17 10 20 2, 8 2, 8, 8 Which statement is correct for both X and Y? A They are atoms of metals. B They are atoms of noble gases. C They are negative ions. D They are isotopes of the same element.

Tanjong Katong Girls’ School Sec 4 Preliminary Examination 2023 12 The shapes and names of some molecules are shown. key : P atom and : other atom Phosphine is a compound of phosphorus, an element in Group V, and hydrogen. What is the shape of a molecule of phosphine likely to be? A bent B linear C pyramidal D tetrahedral 13 Which statement explains why potassium chloride, KCl, has a lower melting point than calcium oxide, CaO? A Potassium is a more reactive metal than calcium. B Potassium chloride is covalent and calcium oxide is ionic. C The melting point of potassium is lower than that of calcium. D The attraction between K+ and Cl- is weaker than Ca2+ and O2-. 14 A mixture of the oxides of two elements from Period 3 of the Periodic Table is dissolved in water. This solution is approximately neutral. What could be the constituents of the mixture? A Al2O3 and MgO B Na2O and MgO C SO3 and P4O10 D Na2O and P4O10 tetrahedral pyramidal bent linear

Tanjong Katong Girls’ School Sec 4 Preliminary Examination 2023 15 Solid G is added in excess to dilute hydrochloric acid. The pH of the solution was monitored during the experiment and a graph was obtained. What could solid G be? A zinc oxide B potassium oxide C sodium sulfate D calcium carbonate 16 The scheme shows the reactions of salt F. What is the identity of salt F? A iron(III) chloride B iron(III) iodide C copper(II) chloride D copper(II) iodide mass of solid G added / g pH 7 green crystalline salt F aqueous salt white precipitate blue precipitate dark blue solution dissolve in water excess aqueous ammonia dilute nitric acid, followed by aqueous silver nitrate aqueous ammonia

Tanjong Katong Girls’ School Sec 4 Preliminary Examination 2023 17 Which reagent can used to distinguish a solution containing Zn2+ ions from a solution containing Al3+? A aqueous ammonia B aqueous lead(II) nitrate C aqueous sodium hydroxide D dilute sulfuric acid 18 In each of three experiments, a h