2024 H1 Chem JC2 Prelim P1 (QP) JPJC

© Jurong Pioneer Junior College [Turn over Name:____________________________________ Class:_____________ JURONG PIONEER JUNIOR COLLEGE JC2 Preliminary Examination 2024 CHEMISTRY 8873/01 Higher 1 2024 Paper 1 1 hour Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and exam index number on the Answer Sheet in the spaces provided unless this has been done for you. There are 30 questions in this section. 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. The use of an approved scientific calculator is expected, where appropriate. This document consists of 9 printed pages and 3 blank pages.

2 © Jurong Pioneer Junior College 8873/01/J2 PRELIMINARY EXAMINATION /2024 1 In two separate experiments a beam of protons and a beam of electrons, travelling at the same velocity, pass through an electric field as shown. Which statements are correct? 1 The electrons are deflected to a larger extent than the protons. 2 The electron beam is deflected in the opposite direction to the proton beam. 3 The proton beam travels in a straight path towards the negatively charged plate. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 3 only 2 The 7th, 8th, 9th and 10th ionisation energies of four consecutive elements in the Periodic Table, P, Q, R and S are shown. element 7th ionisation energy / kJ mol-1 8th ionisation energy / kJ mol-1 9th ionisation energy / kJ mol-1 10th ionisation energy / kJ mol-1 P 9941 18580 21610 25180 Q 10530 12140 22480 25860 R 9520 12810 14530 26740 S 10300 11690 15280 17110 Which element has the highest first ionisation energy? A P B Q C R D S 3 A gaseous mixture containing 10 cm 3 of C 3H8 and 90 cm 3 of oxygen was sparked and C3H8 undergoes complete reaction. The resultant mixture was passed through excess NaOH(aq). What is the final volume of gas remaining after cooling back to room temperature? A 20 cm3 B 40 cm3 C 60 cm3 D 80 cm3

3 © Jurong Pioneer Junior College 8873/01/J2 PRELIMINARY EXAMINATION /2024 [Turn over 4 Use of the Data Booklet is relevant to this question. HFC-134a is a molecule that was developed during the 1980s to replace CFCs that were causing great damage to the ozone layer. The percentage composition by mass of HFC-134a is: C, 23.5%; H, 2.0%; F, 74.5%. Which structural formula could be that of HFC-134a? A CH2FCF3 B CHF2CF3 C CHF3 D CH2F2 5 A 25.0 cm 3 sample of 0.20 mol dm −3 TlNO3 required 25.0 cm 3 of 0.10 mol dm −3 acidified KMnO4 to oxidise it to Tl3+ in solution. What is the oxidation state of the manganese in the reduced form? A +2 B +3 C +4 D +5 6 Silicon carbide, SiC, has the same structure as silicon(IV) oxide, SiO2. Hence, SiC is used as a major industrial abrasive, and a refractory material which is resistant to decomposition by heat. Which type of structure explains these properties? A A simple molecular structure with covalent bonds between silicon and carbon atoms. B A layered structure with covalent bonds between silicon and carbon atoms and weak instantaneous dipole-induced dipole attraction between the layers. C A giant covalent structure with strong covalent bonds between silicon and carbon atoms forming a 3-dimensional network. D A giant ionic lattice with strong ionic bonds holding the oppositely charged ions together. 7 Consider the following four compounds. 1 (CH3)3CH 2 CH3CH2CH2CH3 3 CH3CH2CH2OH 4 CH3CH2Cl What is the order of decreasing boiling point of these compounds? A 1 → 2 → 4 → 3 B 3 → 4 → 1 → 2 C 3 → 4 → 2 → 1 D 4 → 3 → 2 → 1

4 © Jurong Pioneer Junior College 8873/01/J2 PRELIMINARY EXAMINATION /2024 8 Which of the following statement explains why the boiling point of water (100 °C) is higher than that of ammonia (–33 °C)? A There are, on average, more hydrogen bonds between water molecules than there are between ammonia molecules. B The Mr of water is greater than that in ammonia, so instantaneous dipole -induced dipole forces of attraction between water molecules is stronger. C Ammonia has intramolecular hydrogen bonds, which water does not have. D The O–H bond in water is stronger than the N–H bond in ammonia. 9 Phosphorus reacts with chlorine to form both PCl3 and PCl5. However, nitrogen reacts with chlorine, to form only NCl3. Which statement is the best explanation for this? A Nitrogen cannot attain an oxidation state of +5. B The N–Cl bond is weaker than the P–Cl bond. C The valence orbitals of P are higher in energy than that of N. D N does not have vacant low-lying d orbitals to expand octet. 10 Which statements are correct for the sequence of compounds below considered from left to right? NaF MgO AlN SiC 1 The electronegativity difference between the elements in each compound increases. 2 The compounds are isoelectronic. 3 The bonding becomes increasingly covalent. A 3 only B 2 and 3 only C 1 and 2 only D 1, 2 and 3 11 The table shows the thermal decomposition of three hydrogen halides. HCl HBr HI decomposition temperature / oC 1500 1200 500 Why is there a decrease in the decomposition temperature of the hydrogen halides from hydrogen chloride to hydrogen iodide? 1 Induced dipole forces between molecules decrease in strength. 2 Hydrogen bonds between molecules decrease in strength. 3 Covalent bonds between the atoms decrease in strength. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 3 only

5 © Jurong Pioneer Junior College 8873/01/J2 PRELIMINARY EXAMINATION /2024 [Turn over 12 Element X reacts with oxygen to form a high melting point solid which is insoluble in water. When X reacts with chlorine, a low melting point liquid is formed which is soluble in water, giving a solution with a pH of 1. What is X? A magnesium B aluminium C silicon D phosphorus 13 Which difference best explains the variation in melting points across Period 3? A the difference in structure and bonding B the difference in nuclear charge C the difference in number of unpaired electrons D the difference in bond energies 14 Which equation correctly represents the lattice energy of sodium oxide? A 2Na(s) + ½ O2(g) → Na2O(s) B 2Na+(g) + O2−(g) → Na2O(s) C Na(g) + ¼ O2(g) → ½ Na2O(s) D Na+(g) + ½ O2−(g) → ½ Na2O(s) 15 The reaction pathway diagram for a two–step reaction is shown below. Step 1: J K Step 2: K L Which statement is correct? A Step 2 is more exothermic than step 1. B The enthalpy change for both the forward and backward reactions in step 1 is the same. C The activation energy for the backward reaction in step 1 is 61 kJ mol–1. D The enthalpy change of reaction for the conversion of J to L is the sum of the enthalpy changes in step 1 and step 2. progress of reaction energy / kJ mol–1 50 111 138 J K L

6 © Jurong Pioneer Junior College 8873/01/J2 PRELIMINARY EXAMINATION /2024 16 For a reversible reaction, what is the effect of a catalyst on the • rate constant for the forward reaction, k1, • rate constant for the reverse reaction, k−1, an