2024 SCGS Chemistry Prelim P1

CANDIDATE NAME CLASS 4 REGISTER NUMBER CENTRE NUMBER INDEX NUMBER CHEMISTRY 6092/01 PAPER 1 Multiple Choice 28 August 2024 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 on the Answer Sheet in the spaces provided. There are forty questions in this paper. Answer all questions. For each question, there are four possible answers, A, B, C, 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 17. The use of an approved scientific calculator is expected, where appropriate. This question paper consists of 17 printed pages and 1 blank page SINGAPORE CHINESE GIRLS’ SCHOOL PRELIMINARY EXAMINATION SECONDARY FOUR

2 1 Substance X can occur in three different physical states as shown in the diagram. Which statement is correct? A In state 1, the particles vibrate in fixed positions. B Diffusion occurs in the phase change from state 3 to state 2. C The volume of the substance in state 1 is fixed. D Condensation occurs in the phase change from state 1 to state 2. 2 The rate of diffusion of two gases, methane and propene, is investigated. Which gas diffuses at a faster rate and why? Faster gas Reason A propene It is unsaturated so is more reactive. B propene It is lighter so moves faster. C methane It has a lower molecular mass. D methane It has a lower boiling point. 3 The table gives the results of chromatography experiments that were carried out on some known food colours, using the same solvent. Name of food colour Distance form start line to solvent front (mm) Distance moved by food colour spot (mm) Ponceau 4R 60 42 Carmoisine 74 45 Fast red 67 27 Erythrosine 58 17 Which food colour is the most soluble in the solvent used? A Ponceau 4R B Carmoisine C Fast red D Erythrosine

3 4 The diagram shows the fractional distillation of crude oil. Which statement about fractions X and Y is correct? A X is more flammable than Y. B X is more viscous than Y. C X burns with a sootier flame than Y. D X has longer chain molecules than Y. 5 An unknown salt sample, X, has been sent off for analysis and identification using flame emission spectroscopy. In this kind of spectroscopy, atoms of an element each give a characteristic pattern of lines which is known as a line spectrum. A small sample of X loaded into a flame emission spectroscope and its line spectrum was generated. The line spectrum of X was compared to the line spectrums of Group 1 elements to see if the metal ions present in X could be identified. The line spectra are shown below. Which element is not present in X? A Lithium B Sodium C Potassium D Rubidium fraction X fraction Y heated crude oil

4 6 A student reacted excess calcium with hydrochloric acid and carried out a series of tests on the reaction mixture. The results of the tests are given in the table. Which observation does not tell you that this reaction has occurred? Test Observation A Add dilute nitric acid followed by aqueous silver nitrate White precipitate B Weigh the reaction mixture at the start and at the end Mass decreases C Test the pH of the mixture at the start and after 30 s pH increases D Add aqueous sodium hydroxide until no further change White precipitate insoluble in excess sodium hydroxide 7 Elements X and Y combine to form an ionic compound. Atoms of X have more protons than atoms of Y. Atoms of Y have more valence electrons than atoms of X. Which statement is correct? A Ions of X are negatively charged. B Atoms of X have more electron shells than atoms of Y. C X and Y are in the same period of the Periodic Table. D X and Y are in the same group of the Periodic Table. 8 Iridium has two isotopes, 191Ir and 193Ir. The percentage abundance of each isotope in a sample of iridium is given in the table. What is the relative atomic mass of the sample of iridium? A 191.2 B 191.6 C 191.7 D 192.5 Mass number 191 193 Percentage abundance 62.7% 37.3%

5 9 A selenide ion has the following notation. 𝑆𝑆𝑆𝑆34 79 2- Which row correctly describes the sub-atomic particles in the selenide ion? Protons Neutrons Electrons A 32 79 34 B 34 45 32 C 34 45 36 D 45 34 36 10 Which element does not form a stable ion with the same electronic configuration as neon? A Magnesium B Fluorine C Sodium D Sulfur 11 Which of the dot-and-cross diagrams shows the correct arrangement of electrons in the valence shells of lithium sulfide?

6 12 CH4, H2O and HCl are covalent compounds. Which atoms in these compounds do not use all their outer shell electrons in bonding? A C and H B C and O C O and Cl D Cl and C 13 An impure sample of calcium carbonate with a mass of 1.70 g was reacted with excess hydrochloric acid and 360 cm3 of carbon dioxide was collected at room temperature and pressure. What is the percentage purity of the calcium carbonate? A 75% B 88% C 90% D 98% 14 The relative molecular masses of four compounds are given. A student has a 1.0 g sample of each compound. Which sample contains the highest number of moles of oxygen atoms? compound relative molecular mass A Al2O3 102 B CuO 80 C H2SO4 98 D HNO3 63 15 50.0 cm3 of 0.10 mol/dm3 silver nitrate, AgNO3, is added to 150.0 cm3 of 0.05 mol/dm3 of sodium iodide, NaI, in a beaker. After the reaction, solid silver iodide is present in the beaker. What else is present in the mixture? A Ag+, Na+, NO3 - only B Na+, I-, NO3 - only C Na+, I- only D Na+, NO3 - only

7 16 Water is formed when oxygen combines with hydrogen. What mass of oxygen combines with 6 g of hydrogen? A 12 g B 48 g C 96 g D 144 g 17 Which compound has the lowest percentage by mass of nitrogen? A (NH2)2CO B (NH4)2SO4 C (NH4)3PO4 D NH4NO3 18 Cobalt(II) chloride is a soluble salt. What reactants could be used to produce cobalt(II) chloride and what is a suitable method to produce a pure sample of the salt? Reactants Method A cobalt(II) nitrate and hydrochloric acid excess solid + acid B cobalt(II) hydroxide and sodium chloride titration C cobalt(II) sulfate and sodium chloride precipitation D cobalt(II) carbonate and hydrochloric acid excess solid + acid

8 19 Ammonium carbonate reacts with calcium hydroxide to produce a colourless, pungent gas. The set-up for preparation and collection of a moist sample of the gas is shown. Which statements about the moist gas are correct? The gas 1 turns universal indicator blue 2 is denser than air 3 is very soluble in water 4 can be dried by passing it through concentrated sulfuric acid A 1 and 3 only B 2 and 4 only C 1, 3 and 4 only D 1, 2 and 4 only 20 Which property of elements increases from left to right of Period 3 of the Periodic Table? A number of outer shells B metallic character C tendency to get reduced D melting points 21 A solution of a lithium halide and a halogen are mixed. A reaction occurs and the mixture darkens in colour. What are the reactants? A bromine and lithium chloride B iodine and lithium fluoride C chlorine and lithium iodide D chlorine and lithium fluoride Round-bottom flask Ammonium carbonate and calcium hydroxide

9 22 Part of the Periodic Table is shown. The letters are not symbols of the elements. Which statem