DHS H2 Chem 2012 Prelim P1 QP

Name: Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 H2 CHEMISTRY 9647/01 Paper 1 Multiple Choice 20 September 2012 1 hour Additional Materials: Optical Answer Sheet Data Booklet INSTRUCTIONS TO CANDIDATES 1. Write your name, index number and class on this question paper. 2. There are forty 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 a wrong answer. 4. Any rough working should be done in this booklet. 5. You may use a calculator. This question paper consists of 21 printed pages and 1 blank page.  DHS 2012 [Turn over

2 Ó DHS 2012 9647/01 [Turn over Section A For each question there are four possible answers, A , B, C and D. Choose the one you consider to be correct. 1 To determine the mass of arsenic present in a sample of pesticide, all the arsenic was first converted to arsenate ion, AsO 43-. 1.25 x 10 -3 mol of AgNO3 was then added to precipitate AsO 43- as Ag 3AsO4. The excess Ag + ions needed 3.64 cm 3 of 0.054 mol dm-3 KSCN to form silver thiocynate, AgSCN. Calculate the mass of arsenic (Ar = 74.9) present in the sample of pesticide. A 0.015 g B 0.026 g C 0.079 g D 0.488 g 2 In an experiment, a sample was vapourised, ionised and passed through an electric field. Analysis of the deflection occurring at the electric region revealed the following data for the sample. It was observed that a beam of Na + gives an angle of deflection of 4.3°. What are the possible identities of unknown particles, q and r, and the value of a? q r a A Be2+ Br- 22.0° B Be2+ S2- 6.2° C Ba2+ Br- 1.2° D Ba2+ S2- 1.4° + »4.4a

3 Ó DHS 2012 9647/01 [Turn over 3 How many moles of electrons must be removed from each mole of methylbenzene, C6H5CH3, when it is oxidised to benzoic acid, C6H5COOH? A 1 B 2 C 4 D 6 4 Which graph correctly describes the behaviour of fixed masses of the ideal gases I and J, where I has a higher Mr than J? A B C D T PV Constant P I J T PV Constant P J I Constant T J I PV P Constant T I J PV P

4 Ó DHS 2012 9647/01 [Turn over 5 A student used the set–up below to heat a can containing 300 g of water. The following data were recorded: mass of propan–1–ol burnt = m g change in temperature of water = DT °C Given that: relative molecular mass of propan–1–ol = 60.0 enthalpy change of combustion of propan–1–ol = –2021 kJ mol–1 specific heat capacity of water = c J g–1 K–1 What is the efficiency of this heating process? A %. T c m 100060300 10002021 ´´ D ´ ´ ´ ´ B %. T c m10010002021 300 060 ´´ ´ ´ D ´ ´ C %m . T c1002021 060300 ´´ ´ D ´ ´ D %m . T c10010002021 060300 ´´ ´ ´ D ´ ´ 6 Wh