2016 HCI H1 Chemistry Prelims P1 Questions

HWA CHONG INSTITUTION C2 Preliminary Examinations Higher 1 CANDIDATE NAME CT GROUP 15S CENTRE NUMBER INDEX NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Optical Mark Sheet (OMS) Data Booklet 8872/01 21 September 2016 50 min READ THESE INSTRUCTIONS FIRST Write in soft pencil. Complete the information on the optical mark sheet (OMS) as shown below. There are thirty 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 OMS. 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. This question booklet consists of 9 printed pages. Write your name Write and shade your NRIC or FIN number Write your CT group

2 HCI 8872/01 P1 Prelim 2016 SECTION A 1 How many neutrons are present in 0.13 g of 13C? [L = the Avogadro constant] A 0.06 L B 0.07 L C 0.13 L D 0.91 L 2 A protonated oxoanion of vanadium has been characterised at pH 3 with the formula HV10O285r . Which oxoanion contains vanadium in a different oxidation state from that shown in HV10O285r ? A VO2+ B VO2+ C V4O124r D VO3r 3 The double salt (NH4)2SO4.FeSO4.6H2O is used as a standard in volumetric analysis for titrations with oxidising agents. What is the electronic configuration of the metal ion in this salt? A [Ar]4s23d6 B [Ar]4s23d4 C [Ar]3d6 D [Ar]3d5 4 The table shows the successive ionisation energies for an element Q. 1st 2nd 3rd 4th Ionisation energy / kJ mol-1 418 3070 4600 5860 What is the likely formula of the oxide of Q? A QO B Q3O2 C Q2O D Q2O3 5 Which statement about an element in the Periodic Table is correct? A Magnesium is a metalloid, has a giant structure and is a good conductor of electricity B Silicon is a metalloid, has a simple molecular structure and is a semi-conductor of electricity. C Sodium is a metal, has a giant structure and is a good conductor of electricity. D Sulfur is a non-metal, has a giant structure and is a poor conductor of electricity

3 HCI 8872/01 P1 Prelim 2016 6 The metal niobium, Nb, has a relative atomic mass of 92.9 and is used in various stainless steel alloys. It is made by reducing niobium chloride with sodium. In this reaction, 54.08 g of niobium chloride produces 18.58 g of niobium. What is the formula of the niobium chloride used? A NbCl2 B NbCl3 C NbCl4 D NbCl5 7 Which statement about bond formation is not correct? A A triple bond consists of one σ bond and two π bonds. B A π bond restricts rotation about the σ bond axis. C Bonds formed from atomic s orbitals are always σ bonds. D End-to-end orbital overlap results in a bond with electron density above and below the bond axis. 8 Given that both NaOH and KOH are strong mineral bases, calculate the resultant pH when 20 cm3 of 0.300 mol dm-3 of NaOH is mixed with 30 cm3 of 0.200 mol dm-3 of KOH. A 11.8 B 12.1 C 13.4 D 13.7 9 Some data on two acid-base indicators are shown in the table below: Indicator Approximate working range Colour in Acid Alkali methyl orange 3.2  4.4 red yellow bromothymol blue 6.0  7.6 yellow blue Which one of the following conclusions can be drawn about a solution in which methyl orange is yellow and bromothymol blue is yellow? A It is weakly basic. B It is weakly acidic. C It could be a solution of sodium chloride. D It could be a solution of sodium ethanoate. 10 Which of the following 1 dm3 acid solutions will form an acidic buffer when added to 1 dm3 0.100 mol dm3 NaOH? A 0.200 mol dm3 HCl B 0.200 mol dm3 CH3CO2H C 0.050 mol dm3 (COOH)2 D 0.100 mol dm3 H2SO4

4 HCI 8872/01 P1 Prelim 2016 11 Stomach juices have a pH of 1.0. Aspirin is a monobasic acid represented by HA (Ka = 10-4 mol dm-3) which dissociates into H+ and A- ions. What are the relative concentrations of [H+] , [A-] and [HA] when aspirin from a tablet enters the stomach ? A B C D [H+] > [HA] > [A-] [HA] > [H+] = [A-] [H+] > [A-] > [HA] [H+] = [A-] > [HA] 12 The diagram represents the energy changes for some reactions. What are the natures of the conversions W → Y, Y → X and Z → W? W → Y Y → X Z → W A exothermic endothermic endothermic B exothermic exothermic endothermic C endothermic exothermic exothermic D endothermic endothermic exothermic 13 Ethanol is increasingly being used as a fuel for cars. The standard enthalpy change of formation of carbon dioxide is –393 kJ mol–1. The standard enthalpy change of formation of water is –286 kJ mol–1. The standard enthalpy change of formation of ethanol is –277 kJ mol–1. What is the standard enthalpy change of combustion of ethanol? A –1921 kJ mol–1 B –1367 kJ mol–1 C –956 kJ mol–1 D – 402 kJ mol–1

5 HCI 8872/01 P1 Prelim 2016 14 For which equation is the enthalpy change correctly described as an enthalpy change of formation? A C(g) + O2(g) → CO2(g) B C(s) + ½O2(g) → CO(g) C 2N(g) + 4O(g) → N2O4(g) D 2NO(g) + O2(g) → 2NO2(g) 15 Which property is not associated with the element sodium? A It can react with cold water to form hydrogen. B It forms a basic oxide. C It forms a neutral chloride. D It is an oxidising agent. 16 Four compounds of period 3 elements are listed. Na2O SiCl4 SO2 NaCl Water is added to each of the four compounds. Pairs of the resulting solutions are mixed together. From which pair of solutions is it possible to get a solution with a pH of 7? A NaCl and Na2O B NaCl and SO2 C Na2O and SiCl4 D SiCl4 and SO2 17 Phosphorus is an element in the third period, Na to Ar, of the Periodic Table. What is true for phosphorus? A Phosphorus is the only element in this period which forms two acidic oxides. B The chlorides of phosphorus reacts with water to form two acids that are classified as strong and weak acids. C Phosphorus exists as simple molecule with four bonds. D Phosphorus burns in air spontaneously with a bright yellow flame.

6 HCI 8872/01 P1 Prelim 2016 18 Which of the following compounds are arranged in decreasing order of their solubility in water? A CH3CH2CO2Na, CH3CH2CH2OH, CH3CH2CH2Cl B CH3CH2CO2Na, CH3CH2CH2Cl, CH3CH2CH2OH C CH3CH2CH2OH, CH3CH2CO2Na, CH3CH2CH2Cl D CH3CH2CH2Cl, CH3CH2CH2OH, CH3CH2CO2Na 19 Crude oil is a mixture of many hydrocarbons ranging in size from 1 to 40 carbon atoms per molecule. The alkanes in crude oil can be separated because they have different boiling points. The table below shows the boiling points of some alkanes. Alkane Boiling point/ oC Mr pentane 36 72 2-methylbutane 28 72 dimethylpropane 10 72 What is the correct explanation for the difference in the boiling points of the three isomers with Mr = 72? A Boiling point is dependent upon the length of the carbon chain only. B Increased branching on a carbon chain increases the boiling point. C Increased branching reduces the packing density of molecules. D Increased branching reduces the strength of the intermolecular van der Waals’ forces. 20 Which compound cannot be oxidised by acidified potassium dichromate(VI) solution but does react with sodium metal? A (CH3)3COH B CH3COCH2CH3 C CH3CH2CH2CH2OH D CH3CH2CH(OH)CH3 21 Which compound produces butan-2-ol and ethanoic acid on hydrolysis? A CH3CO2CH(CH3)2 B CH3CO2CH(CH3)CH2CH3 C CH3CH(CH3)CO2CH2CH3 D CH3CH2CO2CH(CH3)CH2CH3

7 HCI 8872/01 P1 Prelim 2016 22 How many isomeric esters have the molecular formula C4H8O2? A 2 B 3 C 4 D 5 23 β-carotene is responsible for the orange colour of carrots. β-caro