NYJC H1 Chem Prelim 08 P1

NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 1 CHEMISTRY 8872/01 Paper 1 Multiple Choice 17 September 2008 50 minutes Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, class and tutor’s name on the Answer Sheet in the spaces provided unless this has been done for you. 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 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. This document consists of 13 printed pages. [Turn over

2 Section A For each question there are four possible answers, A, B, C and D. Choose the one you consider to be correct. 1 In an attempt to establish the formula of an oxide of nitrogen, a known volume of the pure gas was mixed with hydrogen and pass ed over a catalyst at a suitable temperature. 100% conversion of the ox ide to ammonia and water was shown to have taken place. N xOy xNH3 + yH2O H2(g) 2400 cm 3 of nitrogen oxide, measured at room temperature and pressure, produced 7.20 g of water. The ammonia produced was neutralised by 200 cm3 of 1.0 mol dm−3 of HCl. What is the oxidation number of the nitrogen in the nitrogen oxide? A +1 B +2 C +3 D +4 2 Which one of the following ions has more electrons than protons, and more protons than neutrons? [D= ] H2 1 A D − B He + C OH − D D 3O+ 3 For which of the following does the 2 nd compound has a higher boiling point than the 1st compound? A pentane and butanone B propene and ethene C 4-nitrophenol and 2-nitrophenol D pentane and 2,2-dimethylpropane H1 Chemistry 8872/01 NYJC J2/08 PX

3 4 Which molecule has the largest dipole? A B C D OC CH3 CH3 CC Cl CH3 H3C Cl CC CH3 CH3 H H OC Cl Cl 5 The enthalpy change when solid sodium hydroxide dissolves in water is − 44.4 kJ mol−1. 250 g of water is placed in a coffee-cup calorimeter containing 13.9 g of solid NaOH. If the solution has the same specific heat c apacity as liquid water, what is the rise in temperature of the solution? A 18 4 250 4 44 9 13 . . . × × K B 310 4 44 9 13 18 4 250 × × × . . . K C ×× ×× 313.9 44.4 10 40 250 4.18 K D 18 4 9 263 10 4 44 9 133 . . . . × × × K 6 Given the following data and energy cycle, what is the enthalpy change for the following reaction? IF5(g) → IF3(g) + F2(g) IF(g) + F 2(g) → IF3(g); ∆H = −390 kJ mol−1 IF(g) + 2F 2(g) → IF5(g); ∆H = −745 kJ mol−1 IF5(g) IF3(g) + F2(g) IF(g) + 2F2(g) A −355 B +355 C −1135 D +1135 H1 Chemistry 8872/01 NYJC J2/08 PX

4 7 The reaction of iodine with propanone in the presence of aqueous acid is zero order with respect to iodine. Which diagram represents the variation of [I2] with time? A B C D [I2] [I2] time time [I2] time [I2] time 8 Two equilibria are shown below. Reaction I: 2NO2(g) 2NO(g) + O2(g) Reaction II: NO(g) + 2 1 O2(g) NO2(g) The numerical value of Kc for reaction I is 4. Under the same conditions, what is the numerical value of Kc for reaction II? A −4 B 1 4 C 1 2 D 2 9 When the system H 2(g) + I2(g) 2HI(g) is in equilibrium at 444°C and 1 atm, the value of the equilibrium constant, Kc, is 50. What is the value of Kc if the pressure is incr eased to 2 atm at the same temperature? (Pressure of a gas is directly proportional to its concentration.) A 25 B 50 C 100 D 200 H1 Chemistry 8872/01 NYJC J2/08 PX

5 10 For the reaction: NH4 +(aq) + CO3 2−(aq) HCO3 − (aq) + NH3(g) Which of the following statements is correct? A CO3 2− is a proton donor. B NH 3 is a proton donor. C HCO3 − is the conjugate base of CO3 2−. D NH4 + is the conjugate acid of NH3. 11 A titration was carried out between a weak acid, HA, and aqueous sodium hydroxide. The graph obtained was shown below: pH 7 volume of NaOH A suitable indicator for the above titration is Indicator pH range A Thymol blue 1.5 to 2.5 B Bromocresol green 3.8 to 5.5 C Bromothymol blue 6.0 to 7.5 D Thymolphthalein 9.3 to 10.5 H1 Chemistry 8872/01 NYJC J2/08 PX

6 12 Ethanedioate ions, C 2O4 2_ , is oxidised by acidified, aqueous potassium manganate (VII) according to the equation: 2MnO4 _ (aq) + 5C2O4 2_ (aq) + 16H+(aq) → 2Mn2+(aq) + 10CO2(g) + 8H2O(l) What volume of 0.0200 moldm-3 potassium manganate (VII) is required to oxidise completely 1.0 × 10-3 mol of the salt KHC2O4H2C2O4? A 20 cm 3 B 40 cm 3 C 50 cm 3 D 80 cm 3 13 In which of the following reactions is the acid acting as an oxidant? A Cu + 2H 2SO4 → CuSO4 + 2H2O + SO2 B KBr + H 3PO4 → HBr + KH2PO4 C 12HC lO4 + P4O10 → 6Cl2O7 + 4H3PO4 D ZnO + 2HNO 3 → Zn(NO3)2 + H2O 14 Which property decreases from Na 2O to SiO2 and also from SiO2 to P4O10? A covalent character B melting point C pH when mixed with water D solubility in aqueous alkali 15 The first ionisation energies, in kJ mol -1, of a sequence of elements of increasing proton (atomic number) are given below: 519 900 799 1090 1400 Where in the Periodic Table is this sequence of elements likely to be located? A Group II B Group VII C from Li to N inclusive D from N to Na inclusive H1 Chemistry 8872/01 NYJC J2/08 PX

7 16 A student isolated an organic com pound with the molecular formula C 4H8. The total number of possible isomers (includi ng structural and geometrical isomers) he can deduce from the molecular formula is A 3 B 4 C 5 D 6 17 Which substance in a vehicle exhaust re sults from incomplete combustion of a hydrocarbon fuel? A CO B H 2O C N 2 D NO 18 A hydrocarbon C 6H8 on refluxing with acidified potassium manganate (VII) produces the structure below as the only organic product. C H CO2H CH3 CO2H What could be a possible structure of the hydrocarbon? A CH3 B CH3 C CH3 D CH3 H1 Chemistry 8872/01 NYJC J2/08 PX

8 19 Which of the following reactions would not produce CO2H CO2H ? A CH2CH3 CH3 + acidified KMnO 4, reflux B COCH3 COCH3 + alkaline aqueous iodine, warm followed by acidification C CHO CHO + Tollens’ reagent, warm followed by acidification D CH2CN CO2CH3 + aqueous H 2SO4, reflux H1 Chemistry 8872/01 NYJC J2/08 PX

9 20 The following compound was heated with alcoholic potassium hydroxide. Cl Cl CH3 C H3 O H Which of the following represents the structure of the organic product? A OH OH CH3 C H3 O H B CH3 C H3 O H C Cl Cl CH3C H2 D Cl Cl CH3C H3 21 Which one of the following substances will give an alcohol upon heating under reflux with aqueous sodium hydroxide? A (CH 3CH2)2O B CH 3CH2CO2CH3 C CH 3CH=CH2 D C 6H5Br 22 Which one of the following compounds is unaffected by hot ac idified potassium manganate (VII) and gives hydrogen when treated with sodium? A (CH 3)3COH B (CH 3)2CHCH2OH C CH 3CH2CH(OH)CH3 D (CH 3)2CHCOCH3 H1 Chemistry 8872/01 NYJC J2/08 PX

10 23 Which of the following compounds can undergo the tri-iodomethane test? A C H H H C O O H B C H H H C H O H H C C H O O C H H H D C H H O C H H HH 24 Citric acid, which causes the sharp taste of lemon juice, has the following formula. CC O 2H CH2CO2H CH2CO2H HO Which of the following reacts completely with 1 mol of citric acid? A 3 mol of PC l5(s) B 4 mol of HC l(g) C 4 mol of Na(s) D 4 mol of NaOH(aq) 25 Why is propanoic acid, CH 3CH2COOH, a stronger acid than propanol, CH3CH2CH2OH?