2024 Prelims TJC H2 Chem P1 (QP)

1 9729 / TJC Prelims / 2024 TEMASEK JUNIOR COLLEGE 2024 JC2 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 12 September 2024 1 hour Additional Materials: Multiple Choice Answer Sheet (OMS) Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. There are thirty 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. Write your name & Civics Group on the Answer sheet. Shade your index number in the appropriate boxes. 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 14 printed pages and 2 blank pages. Write your name and Civics Group Index number (refer to entry proof)

2 9729 / TJC Prelims / 2024 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 (OMS). 1 Use of the Data Booklet is relevant to this question. Chlorine radicals is one of the main chemical species responsible for the depletion of ozone from the stratosphere. What does 35Cl contain? protons neutrons electrons A 18 35 17 B 18 35 18 C 17 18 17 D 17 18 18 2 Which compound is composed of cation and anion that has the same number of electrons as each other? 1 K2O2 2 NaN3 3 NH4F 4 K2CO3 A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4 3 Use of the Data Booklet is relevant to this question. The sixth ionisation energies of four different elements are shown below. The elements are arsenic, selenium, antimony and tellurium (though not necessarily in that order) from Groups 15 and 16. Which of the following shows the sixth ionisation energy of antimony? A 12300 B 10400 C 7880 D 6820

3 9729 / TJC Prelims / 2024 [Turn over 4 Trimethoprim (TMP) is used for the treatment of urinary tract infections. It has the following structure: Which are the correct bond angles w, x, y and z? w x y z A 90 180 120 90 B 90 105 118 107 C 109.5 105 120 107 D 109.5 180 118 120 5 Beryllium chloride, BeC l2, reacts with methylamine, CH 3NH2 to form a compound. Which of the statements is incorrect? A The compound is formed from 1 mole of BeCl2 and 2 moles of CH3NH2. B The Be-N bond formed is chemically similar to a covalent bond. C The beryllium atom in beryllium chloride is electron deficient. D The compound is capable of forming only two hydrogen bonds per molecule. 6 In which of the following pairs of compounds would the first compound have a higher melting point than the second compound? A K2O, Na2O B AlCl3, AlF3 C NH2CH2CO2H, HOCH2CO2H D ,

4 9729 / TJC Prelims / 2024 7 Use of the Data Booklet is relevant to this question. A solution containing 25 cm 3 of 0.1 mol dm -3 VO2+ reacts completely with 0.245 g of zinc. Which of the following can be the vanadium-containing species in the product? A VO3– B VO2+ C V3+ D V2+ 8 Which graph is a correct representation of Charles’ Law? A B C D 9 The three minerals below are obtained from mines around the world. Each one behaves as a mixture of two carbonate compounds. They can be used as fire retardants because they decompose in the heat, producing CO 2. This gas smothers the fire. Barytocite BaCa(CO3)2 Dolomite CaMg(CO3)2 Huntite Mg3Ca(CO3)4 What is the order of effectiveness as fire retardant, from best to worst? best worst A huntite dolomite barytocite B huntite barytocite dolomite C dolomite huntite barytocite D dolomite barytocite huntite P/ Pa 1 V / m-3 0 0 P/ Pa 1 V / m-3 0 0 V/ m3 T/°C 0 0 V/ m3 T/°C 0 0

5 9729 / TJC Prelims / 2024 [Turn over 10 The graph below shows the variation in the second ionisation energies for the consecutive elements Q to Z in the Periodic Table, all with proton number below 20. What can be deduced from the above? 1 T has a smaller atomic radius than U. 2 Effervescence is observed when a magnesium strip is dipped into the aqueous solution containing the chloride of element W. 3 When the oxide of U is mixed with water, an alkaline solution is formed. A 1, 2 and 3 B 1 and 2 C 2 and 3 D 3 only 11 Which sample contains the same number of the named species as the number of molecules in 1 g of hydrogen? A Atoms in 23.0 g of sodium B Electrons in 1 g of helium C Ions in 26.5 g of sodium carbonate D Molecules in 44 g of carbon dioxide

6 9729 / TJC Prelims / 2024 12 When 25 cm3 of 1.0 mol dm−3 sodium hydroxide was neutralised with an equal volume of 0.5 mol dm−3 sulfuric acid, the temperature of the mixture rose by 7.0°C. What would be the temperature change if 50 cm3 of 0.5 mol dm−3 sodium hydroxide is neutralised with an equal volume of 0.25 mol dm−3 sulfuric acid? (Assume negligibe heat loss in each case.) A 1.8°C B 3.5°C C 7.0°C D 14°C 13 After the closure of a chemical plant in Switzerland, a substitution reaction between a halogenoalkane, R, and hydrogen sulfide ions is found to take place. initial concentration of R / mol dm-3 initial concentration of hydrogen sulfide ions / mol dm-3 initial rate of reaction / mol dm-3 s-1 0.1 0.1 1.5 x 10-5 0.2 0.1 3.0 x 10-5 0.1 0.2 3.0 x 10-5 0.3 x 1.125 x 10-5 What conclusions can be drawn about the reaction? A The value of x is 0.025. B R could be 2-bromo-2-methylpropane. C The value of the rate constant is 1.5 x 10-4. D Only R is involved in the rate determining step.

7 9729 / TJC Prelims / 2024 [Turn over 14 The kinetics of a reaction P → Q were investigated under different conditions. The following graph was obtained. Which of the following statements about the reaction is correct? A The unit of the rate constant is s-1. B A curve is obtained when [P] is plotted against time. C The same graph is obtained when the [P] is plotted against rate constant. D The rate constant remained unchanged when reaction is repeated at a higher temperature. 15 A(g) + 3B(g) ⇌ 2C(g) A 2 dm3 vessel containing 2.00 mol of A, 6.00 mol of B, and 2.40 mol of C is allowed to reach equilibrium. It was found that there was 2.32 mol of A was present at equilibrium. The reaction was repeated using a 4 dm 3 vessel. The equilibrium amount of A was found to be y mol. What of the following statements about the above reaction is correct? A The concentration of C at equilibrium is 1.76 mol dm-3 in the first experiment. B The value of Kc of the second experiment is smaller than the first experiment. C The unit of the equilibrium constant is mol2 dm-6. D y is larger than 2.32 mol. [P] rate

8 9729 / TJC Prelims / 2024 16 Which of the following statements is correct about the 3 molecules below? A All three molecules are constitutional isomers. B There is a plane of symmetry in molecule 1. C All three molecules are optically active. D Only molecule 1 is optically active. 17 Compound S has strong anti-tumour and antiviral activities. Which of the following statements of compound S is correct? A There are four chiral centers. B There are a total of 8 stereoisomers. C The bond length between C1-C2 is the same as C4-C5. D After reacting with lithium aluminium hydride in dry ether, all the carbon atoms are sp3 hybridised.