plmgs comb chem prelim 2024 paper 3

1 SCIENCE 5105 & 5107/03 Paper 3 Chemistry 30 July 2024 (Taken together with Paper 4) 1 hour 15 mins READ THESE INSTRUCTIONS FIRST Write your name and index number on all the work you hand in. Do not use staples, paper clips, highlighter, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. There are twenty questions in this paper. For each question, four possible answers are given. Choose the one you consider correct and record your choice in soft pencil on the separate optical Answer Sheet. You are advised to spend no more than 30 minutes on Paper 3 and 45 minutes on Paper 4. You may proceed to Paper 4 as soon as you have completed Paper 3. The number of marks is given in brackets [ ] at the end of each question or part question. A copy of the Periodic Table is printed on page 10. This document consists of 10 printed pages. CANDIDATE NAME CLASS CLASS INDEX NO CENTRE NUMBER S INDEX NO Paya Lebar Methodist Girls’ School (Secondary) Preliminary Examination 2024 Secondary 4 Normal Academic / G2 [Turn over

2 1 A student wishes to add exactly 17.20 cm3 of acid to exactly 25.0 cm3 of an alkali as part of an experiment. Which apparatus should the student use to measure these volumes? acid alkali A burette measuring cylinder B burette pipette C measuring cylinder pipette D pipette burette 2 Lead(II) chloride is an insoluble salt which is formed in the reaction of aqueous lead(II) nitrate with aqueous potassium chloride. How is pure lead(II) chloride obtained after the reaction? A crystallisation → evaporation B evaporation → washing and drying C filtration → evaporation D filtration → washing and drying 3 A new element has seven electrons in its outermost shell. Which statement about the element is correct? A It is monoatomic. B It forms a positive ion, X+. C It forms a diatomic molecule. D It forms covalent compounds with sodium.

3 4 What is the chemical formula of iron(II) sulfate? A FeS B FeSO4 C Fe(SO4)2 D Fe2SO4 5 The nucleon number and proton number of an atom of X and an atom of Y are shown. X Y nucleon number 39 40 proton number 19 18 Which statement about X and Y is correct? A An atom of X has fewer electrons than an atom of Y. B An atom of X has fewer neutrons than an atom of Y. C X is above Y in the same group of the Periodic Table. D X is in the same period in the Periodic Table as Y. 6 The table shows the results of adding dilute hydrochloric acid, HCl, and aqueous sodium hydroxide, NaOH to four metal oxides (A, B, C and D). Which of the metal oxides displays amphoteric properties? addition of dilute HCl addition of aqueous NaOH A no reaction no reaction B no reaction reaction C reaction no reaction D reaction reaction [Turn over

4 7 The table shows the boiling points of some substances present in air. substance boiling point / °C argon -186 nitrogen -196 oxygen -183 carbon dioxide -79 Which substance(s) is/are liquid(s) at −150 °C? A carbon dioxide only B carbon dioxide and nitrogen C oxygen and argon D nitrogen, oxygen and argon 8 The electronic structure of two atoms, X and Y, are shown. X and Y combine to form a compound. What is the type of bonding in the compound and what is the chemical formula of the compound? type of bonding chemical formula A covalent X2Y B covalent XY2 C ionic X2Y D ionic XY2

5 9 Sodium is the 6th most abundant element in the Earth’s crust while gold is ranked 72nd. However, gold was discovered long before sodium. Why is sodium more abundant but harder to discover than gold? A Gold exists in an uncombined form but sodium is combined with other elements. B Gold has a higher density than sodium. C Sodium is a softer metal than gold. D Sodium is less pure than gold. 10 Aqueous hydrochloric acid is added to aqueous ammonium carbonate. A gas is given off. Which of the following is a property of the gas? A A green colour is observed when the gas is tested with Universal Indicator. B A white precipitate is formed when the gas is bubbled into limewater. C The gas extinguishes a lighted splint with a ‘pop’ sound. D The gas turns moist red litmus blue. 11 Which of the following compounds cannot be used to control soil acidity? A calcium carbonate B calcium chloride C calcium hydroxide D calcium oxide [Turn over

6 12 The figure below illustrates the reaction between magnesium and steam. Which equation represents the reaction taking place? A Mg + H2O → MgO + H2 B Mg + 2H2O → MgOH2 + H2 C Mg + 2H2O → Mg(OH)2 + H2 D Mg + H2O → no reaction 13 Which volume of air contains approximately 20 cm3 of oxygen? A 20 cm3 B 40 cm3 C 80 cm3 D 100 cm3 14 The list shows some physical properties of metals. 1. good conductors of electricity 2. soft solids 3. high densities 4. high melting points Which properties do the metals in Group 1 of the Periodic Table have? A 1 only B 1 and 2 C 2 and 3 D 1, 2, 3 and 4

7 15 The pH values of four aqueous solutions are shown. solution pH P 3 Q 5 R 9 S 11 If pairs of solutions are mixed, which pair must produce an alkaline solution? A P and Q B P and S C Q and R D R and S 16 The equation shows the reaction that occurs when propene burns completely in air. wC3H6 + 9O2 → yCO2 + zH2O Which values of w, x, y and z balance the chemical equation? w y z A 1 1 2 2 3 3 B 6 6 C 3 3 D 6 6 17 Which of the following represents a substitution reaction? A C10H22 → C4H8 + C6H14 B C3H6 + Cl2 → C3H6Cl2 C CH4 + Cl2 → CH3Cl + HCl D (C2H4)n → [-CH2CH2-]n [Turn over

8 18 Which property of alkanes decreases as the molecular masses of alkanes increase? A flammability B boiling point C melting point D viscosity 19 The diagram shows part of a polymer molecule. Which monomer was used to make this polymer? A B C D

9 20 The table shows the type and number of bonds that are present in compound X. type of bond number of bonds C–C several C=C several O–H one C–H several What type of compound is X? A alkane B hydrocarbon C monounsaturated D polyunsaturated End of paper 3 Answers to 4NA Sci Chem Prelim P3 2024 1 B 2 D 3 C 4 B 5 B 6 D 7 A 8 A 9 A 10 B 11 B 12 A 13 D 14 B 15D 16 D 17 C 18 A 19 C 20 D

10 The Periodic Table of Elements Group 1 2 13 14 15 16 17 18 Key 1 H hydrogen 1 2 He helium 4 3 Li lithium 7 4 Be beryllium 9 proton (atomic) number atomic symbol name relative atomic mass 5 B boron 11 6 C carbon 12 7 N nitrogen 14 8 O oxygen 16 9 F fluorine 19 10 Ne neon 20 11 Na sodium 23 12 Mg magnesium 24 3 4 5 6 7 8 9 10 11 12 13 Al aluminium 27 14 Si silicon 28 15 P phosphorus 31 16 S sulfur 32 17 Cl chlorine 35.5 18 Ar argon 40 19 K potassium 39 20 Ca calcium 40 21 Sc scandium 45 22 Ti titanium 48 23 V vanadium 51 24 Cr chromium 52 25 Mn manganese 55 26 Fe iron 56 27 Co cobalt 59 28 Ni nickel 59 29 Cu copper 64 30 Zn zinc 65 31 Ga gallium 70 32 Ge germanium 73 33 As arsenic 75 34 Se selenium 79 35 Br bromine 80 36 Kr krypton 84 37 Rb rubidium 85 38 Sr strontium 88 39 Y yttrium 89 40 Zr zirconium 91 41 Nb niobium 93 42 Mo molybdenu m 96 43 Tc technetium – 44 Ru ruthenium 101 45 Rh rhodium 103 46 Pd palladiu