NJC 2022 H1 Chem Promo P1 QP

NJC SH1 Promotional Examination 8873/01/2022 [Turn over 1 NATIONAL JUNIOR COLLEGE SH1 Promotional Examination Higher 1 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Optical Answer Sheet Data Booklet 8873/01 29 September 2022 40 mins READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, subject class and registration number on the Answer Sheet in the spaces provided unless this has been done for you. There are twenty questions on 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. The use of an approved scientific calculator is expected, where appropriate. Instructions on how to fill in the Optical Mark Sheet Shade the index number in a 5 digit format on the optical mark sheet: 2nd digit and the last 4 digits of the Registration Number. Example: Student Examples of Registration No. Shade: 2205648 25648 This document consists of 8 printed pages.

NJC SH1 Promotional Examination 8873/01/2022 2 1 How many hydrogen atoms are present in 4.0 g of methane? (L = Avogadro constant) A L 16 B L 4 C L D 4L 2 The table shows the relative abundance of a sample of naturally occurring isotopes of zinc. isotope relative abundance Zn30 64 10 Zn30 65 8 Zn30 67 2 Zn30 68 1 What is the relative atomic mass of this sample of zinc? A 64.0 B 64.9 C 68.1 D 72.2 3 Analysis of a mixture of two sulfur-containing gases show that H2S and CS2 are present in a 3 : 1 mole ratio. This mixture is burned in excess oxygen to give CO2 and SO2 gas. What is the mole ratio of the gases CO2 : SO2 obtained after complete combustion? A 1 : 2 B 1 : 3 C 1 : 4 D 1 : 5 4 2 moles of an oxidising agent, XO4−, in the presence of excess acid, oxidised 96.0 dm3 of nitrogen dioxide gas to NO3− at room temperature and pressure. What is the number of moles of electrons accepted by one mole of XO4−? A 1 B 2 C 3 D 4

NJC SH1 Promotional Examination 8873/01/2022 [Turn over 3 5 The first six ionisation energies of an element, Y, in kJ mol‒1 are shown. 1st 2nd 3rd 4th 5th 6th Ionisation Energy / kJ mol−1 738 1451 7733 10543 13630 18020 Y forms an oxide by heating Y with oxygen gas. What is the molecular formula of the oxide of Y formed? A YO B YO2 C Y2O D Y2O3 6 The radioactive isotope Ra223 88 decays to give Q and emits a high energy α-particle, He2 4 . No other particle is produced. Ra223 88 ⎯→ He2 4 + Q How many neutrons are present in Q? A 86 B 133 C 135 D 219 7 Why is the second ionisation energy of fluorine lower than that of oxygen? A There are more paired electrons in the 2p orbitals of fluorine than in oxygen. B The ionic radius of O+ is greater than F+. C Fluorine has a lower nuclear charge compared to oxygen. D All 2p orbitals of O+ are singly filled but one of the 2p orbitals of F+ is doubly filled. 8 Chlorine atoms in the PCl5 molecule can be successively replaced by fluorine atoms, with the axial chlorine atoms replaced before the equatorial ones. Which of the possible molecules formed in the above reaction does not have a net dipole moment? A PClF4 B PCl2F3 C PCl3F2 D PCl4F

NJC SH1 Promotional Examination 8873/01/2022 4 9 Q has the following physical properties. • It is non-volatile. • It does not conduct electricity in its standard state. • It dissolves in water. What is the identity of Q? A Magnesium B Carbon dioxide C Silicon dioxide D Sodium chloride 10 Which statement best explains why the boiling point of butanone (80 C) is higher than that of pentane (36 C)? A The covalent bonds in the butanone molecule are stronger than those in the pentane molecule. B The relative molecular mass of butanone is higher than that of pentane. C There are permanent dipole-permanent dipole forces between butanone molecules, but not between pentane molecules. D There are hydrogen bonds between butanone molecules, but not between pentane molecules. 11 Which option is correct for the following organic molecule? O No. of  bond No. of  bond A 9 2 B 18 2 C 19 4 D 21 2

NJC SH1 Promotional Examination 8873/01/2022 [Turn over 5 12 Use of the Data Booklet is relevant to this question. Hexamine has an enthalpy change of combustion of −4288 kJ mol−1. 12.4 g of hexamine tablets were burnt to heat up 850 cm3 of water. Given that the process was 75 % efficient and temperature of the water increased from 10 C to 90 C, what is the molar mass of hexamine? A 105.2 g mol−1 B 140.3 g mol−1 C 187.1 g mol−1 D 249.4 g mol−1 13 Use of the Data Booklet is relevant to this question. A reaction which causes the presence of oxides of nitrogen in car exhausts is the formation of NO. N2(g) + O2(g) ⎯→ 2NO(g) ∆H = +180 kJ mol–1 What is the bond energy in NO, in kJ mol–1? A 630 B 810 C 1260 D 1440 14 The reaction of a compound XY is shown below. XY(g) ⎯→ X(g) + Y(g) The rate equation for the reaction is rate = k[ XY] and the half-life is 193s . If the initial concentration of XY is 2.0 × 10−2 mol dm−3, what will be the concentration of XY after 770 seconds? A 1.0 × 10–2 mol dm−3 B 5.0 × 10–3 mol dm−3 C 2.5 × 10–3 mol dm−3 D 1.25 × 10–3 mol dm−3

NJC SH1 Promotional Examination 8873/01/2022 6 15 The graph represents the decomposition of a sample of hydrogen peroxide in the presence of manganese(IV) oxide. Which conclusions can be drawn from the graph? 1 The rate of decomposition of hydrogen peroxide depends on its concentration in the sample. 2 The half-life of the hydrogen peroxide in the sample is 200s. 3 The reaction is first order with respect to hydrogen peroxide. A 1, 2 and 3 B 2 and 3 only C 1 and 2 only D 1 and 3 only 16 The diagram shows the structure of a catalytic converter fitted in the exhaust system of a car where harmful gases are converted into carbon dioxide, nitrogen and water vapour. catalytic converter Which reactions would occur on the surface of the catalyst in the catalytic converter? 1 hydrocarbons + oxides of nitrogen ⎯→ carbon dioxide + water + nitrogen 2 carbon monoxide + oxides of nitrogen ⎯→ carbon dioxide + nitrogen 3 carbon monoxide + hydrocarbon ⎯→ carbon dioxide + water A 1, 2 and 3 B 2 and 3 only C 1 and 2 only D 1 and 3 only

NJC SH1 Promotional Examination 8873/01/2022 [Turn over 7 17 Which pairs of molecules are constitutional isomers? 1 CH3CH2CH(CH3)2 and (CH3)4C 2 butanone and 2−methylpropanal 3 C C Cl Cl H H and C C H Cl H Cl A 1, 2 and 3 B 2 and 3 only C 1 and 2 only D 1 and 3 only 18 How many isomeric alkenes with formula C 5H8 are present in the mixture produced when 1,4-dibromopentane is heated with NaOH in ethanol? A 1 B 2 C 3 D 4 19 Which compound is a product of the hydrolysis of CH3CO2CH2CH2CH3