DHS H1 CHEM P1 QP ans FINAL

This question paper consists of 12 printed pages and 0 blank page. © DHS 2015 [Turn over Name: Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination 2015 Year 6 H1 CHEMISTRY 8872/01 Paper 1 Multiple Choice 29 September 2015 50 minutes Additional Materials: Optical Mark Sheet Data Booklet INSTRUCTIONS TO CANDIDATES 1 Write your name and class on this question paper. 2 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 separate Optical Mark Sheet. 3 Each correct answer will score one mark. A mark will not be deducted for wrong answer. 4 Any rough working should be done in this booklet. 5 You may use a calculator.

2 © DHS 2015 8872/01 Section A For each question, there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 10 cm 3 of gaseous hydrocarbon was completely burnt in 80 cm 3 of oxygen (present in excess) at 425 K. After cooling to room temperature, the volume of the gaseous mixture decreased to 55 cm3. A further reduction of 40 cm3 was observed when the residual gas was passed through calcium hydroxide. All gas volumes were measured at room temperature and pressure. What is the formula of the hydrocarbon? A C3H8 B C4H8 C C4H10 D C5H12 2 Chlorine gas is a severe irritant to the eyes and respiratory system. The maximum safe toleration level of chlorine gas in air is 0.005 mg dm –3. How many atoms of chlorine gas are present in 2 dm 3 of air at this toleration level? A 2310671 2 1000 005.0 xxx B 2310671 4 1000 005.0 xxx C 231061000271 005.0 xxxx D 23106471 005.0 xxx 3 0.5 g of zinc powder was found to reduce an acidified solution of 25.50 cm 3 of 0.200 mol dm–3 VO2 +. Which one of the following is the reduced product of VO2 +? A VO3 – B VO2+ C V3+ D V2+ 4 In 1999 Russian chemists claimed to be the first to identify atoms of a new element of proton number 114. This was produced by bombarding atoms of plutonium, Pu, with atoms of an isotope of a Group II element, X. This reaction taking place is as shown:    nneutronselementnewXPu 1 0 289 114 244 94 3 What is element X? A Mg B Ca C Sr D Ba

3 © DHS 2015 8872/01 5 Which of the following chemical species contains the most number of unpaired electrons? A P– B N2– C Ti+ D Cu+ 6 The elements P and Q are in groups VI and VII respectively in the same period. Which of the following statements regarding P and Q is most likely to be true? A PQ2 is linear in shape. B PQ4 is a non–polar molecule. C P is more electronegative than Q. D The first ionisation energy of P will likely be less endothermic than that of Q. 7 The interhalogen compound BrF3 is a volatile liquid which autoionises as follows. 2BrF3 BrF 2 + + BrF4 – The electrical conductivity of BrF3 decreases with increasing temperature. Which one of the following statement is correct? A The autoionisation process is endothermic and the shape of the anion is square planar. B The autoionisation process is exothermic and the shape of the cation is linear. C The autoionisation process is endothermic and the shape of the anion is tetrahedral. D The autoionisation process is exothermic and the shape of the cation is bent. 8 Phosgene, COC l2, is a poisonous gas used as a chemical weapon in World War I. It can dissociate into two other poisonous gases, carbon monoxide and chlorine, at high temperatures according to the equilibrium below: COC l2 (g) CO (g) + C l2 (g) When 1 mol of phosgene is heated in a 2 dm 3 closed vessel at 600 K, 0.2 mol of phosgene remains at equilibrium, what is the numerical value of Kc at 600 K? A 0.025 B 0.25 C 1.6 D 3.2

4 © DHS 2015 8872/01 9 H2PO4 – + HBO3 2– HPO4 2– + H2BO3 – The equilibrium constant for the reaction represented by the equation above is greater than 1.0. Which of the following gives the correct relative strengths of the acid and base in the reaction? Acids Bases A H2PO4 – > H2BO3 – and HBO 3 2– > HPO4 2– B H2BO3 – > H2PO4 – and HBO 3 2– > HPO4 2– C H2PO4 – > H2BO3 – and HPO 4 2– > HBO3 2– D H2BO3 – > H2PO4 – and HPO 4 2– > HBO3 2– 10 Which of the following is a suitable indicator for the titration between 0.10 mol dm –3 ethanoic acid and 0.2 mol dm–3 sodium hydroxide? A methyl red (pH range 4.2 – 6.3) B bromothymol blue (pH range 6.0 – 7.6) C phenolphthalein (pH range 8.2 – 10) D There is no suitable indicator. 11 The table shows the enthalpy change of neutralisation per mole of water formed, H, for various acids and bases. acid base H / kJ mol−1 hydrochloric acid sodium hydroxide −57.0 P sodium hydroxide −51.0 hydrochloric acid Q −52.0 sulfuric acid R −57.0 What are P, Q and R? P Q R A ethanoic acid ammonia barium hydroxide B ethanoic acid sodium hydroxide ammonia C sulfuric acid ammonia potassium hydroxide D sulfuric acid sodium hydroxide ammonia

5 © DHS 2015 8872/01 12 Given the general energy cycle for NaH, Na(s) + 1/2H2(g) Na+(g) + H-(g) NaH(s) Which value is essential to calculate the lattice energy of the compound NaH? A Enthalpy change of combustion. B Enthalpy change of neutralisation. C Bond energy of sodium. D Enthalpy change of formation. 13 The reaction between gaseous hydrogen and iodine monochloride is highly exothermic. The overall equation of the reaction is shown below: H2(g) + 2ICl(g) → I2(g) + 2HCl(g) 3 experiments were carried out to study the rate of the above reaction. Experiment Number Initial concentration of H2 / mol dm–3 Initial concentration of ICl / mol dm–3 Initial reaction rate / mol dm–3 s–1 1 2.0 2.0 0.0034 2 4.0 1.0 0.0034 3 2.0 1.0 0.0017 Which of the following statement about this reaction is true? A The rate equation is rate = k[H2][ICl]2. B The overall order of the reaction is 1. C The units of rate constant is mol–1 dm3 s–1. D The order of reaction with respect to H2 is 2.

6 © DHS 2015 8872/01 14 Given that the radioactive decay follows a first order kinetics. What is the half–life of a radioactive isotope if its rate of decay decreases from 300 counts per minute to 37.5 counts per minute after 1 day? A 4 hours B 6 hours C 8 hours D 12 hours 15 A mixture of 3–chloromethylbenzene and liquid bromine is placed in a sunny spot in the laboratory for a period of time. The reaction that occurs takes place in a number of steps to give several products. CH3 Cl 3–chloromethylbenzene Which of the following is not a possible product? A CBr3 Br C CHBr2 Cl B CH2 Cl CHBr Cl D HBr 16 An organic compound has the following properties: (i) It forms a brick–red precipitate with Fehling’s solution. (ii) 1 mol of the compound gives 2 mol of CO 2 upon oxidation with KMnO4. (iii) 1 mol of the compound burns in air by reacting with 6.5 mol of O 2 gas. Which compound could give these results? A CH 3COCH2C(OH)(CH3)CH2CHO B HCOCH=CHCH(CH3)CO2H C CH2=CHCH2COCH2CH=CH2 D CH3(CH2)2C6H4CHO

7 © DHS 2015 8872/01 17 What would be obtained when 2–methylbut–2–ene is heated under reflux with concentrated sulfuric acid, followed by water? A CH3 CH3 CH3 OH Major product CH3 CH3 CH3 OH Minor product B CH3 CH3 CH3 OH OH Sole product C CH3 CH3 CH3 OH CH3 CH3 CH3 OH Both products in same proportion D CH3 CH3 CH3 OH Sole product 18 A substance, X, is oxidised by acidified potassium dichromate( VI) solution