NYGH 2011-S3EOY-Chem P2

Class Register Number Name 南洋女子中学校 NANYANG GIRLS’ HIGH SCHOOL End-of-Year Examination 2011 Secondary Three CHEMISTRY 1 hour 45 minutes Paper 2 Structured Questions 09 15 to 11 00h Thursday 13 October 2011 Additional materials: Writing papers READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name, register number and class in the spaces at the top of this page and on any separate writing paper used. Section A (40 marks) Answer all questions. Write your answers in the spaces provided on the question paper. Section B (30 marks) Answer all questions including questions 9, 10 and 11 Either or 11 Or. Write your answers on the writing paper provided. At the end of the examination, 1. hand in Section A and Section B separately. 2. fasten all your written papers for Section B securely with the strings provided. 3. tick 11 Either (for Either) or 11 Or (for Or) in the grid below to indicate which question you have answered. INFORMATION FOR CANDIDATES The intended number of marks is given in the brackets [ ] at the end of each question or part question. You are advised to spend no longer than one hour on Section A and no longer than 45 minutes on Section B. Use of Scientific Calculator is allowed. A copy of the Periodic Table is found on page 15. Examiner’s Use Section A Section B 9 10 11 Either 11 Or Total Setters: GB/AS/ET This document consists of 15 printed pages. NANYANG GIRLS’ HIGH SCHOOL [Turn over

2011 End-of-Year Examination Secondary Three 2 Nanyang Girls’ High School Setters: GB/AS/ET Chemistry /II Section A Answer all questions. Write your answers in the spaces provided. A1 Answer the questions below by using the reagents listed below. Cu(s) AgNO 3(aq) H 2SO4(aq) Na2CO3(aq) NaOH(aq) Cu(NO 3)2(aq) (NH4)2SO4(aq) BaC l2(aq) Zn(s) Each reagent may be used once, more than once, or not at all. Give two reagents which when mixed together (a) would produce a soluble salt and a gas by using the titration method. .................................................................................................................................. [1] (b) would produce a blue precipitate. ................................................................................................................................... [1] (c) would produce an alkaline gas upon warming. ................................................................................................................................... [1] [Total marks: 3]

2011 End- of-Year Examination Secondary Three 3 Nanyang Girls’ High School Setters: GB/AS/ET Chemistry /II [Turn over A2 (a) The following questions refer to the diagram below. Answer the following questions using the gases listed below. hydrogen (H 2) oxygen (O2) helium (He) nitrogen (N2) methane (CH4) carbon monoxide (CO) Each gas may be chosen once, more than once, or not at all (i) Which two gases, when placed into A and B respectively, will cause the water level at P to move up initially? Explain your answer. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... [2] (ii) What would be observed in the diagram above if A is helium at room temperature and B is helium at 60°C? Explain your answer. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... [2]   A  B  air air  porous  pots  P Q water

2011 End-of-Year Examination Secondary Three 4 Nanyang Girls’ High School Setters: GB/AS/ET Chemistry /II A2 (b) Some inks are dyes dissolved in water. The apparatus below illustrates how water may be separated from these inks. (i) On the diagram, label the ink and the pure water. [1] (ii) On the diagram, draw a thermometer to show where it should be suitably placed so as to collect pure water in the experimental set-up. [1] (iii) Name this method of separation. ......................................................................................................................... [1] (iv) What is the purpose of the beaker of cold water? ............................................................................................................................ [1] [Total marks: 8] cold water Heat

2011 End- of-Year Examination Secondary Three 5 Nanyang Girls’ High School Setters: GB/AS/ET Chemistry /II [Turn over A3 (a) Tartaric acid is a weak dibasic organic acid that can be extracted from grape juice. It is purified by recrystallization. The structure of tartaric acid is shown below. (i) Define weak acid. .......................................................................................................................... [1] (ii) Tartaric acid reacts with aqueous potassium hydroxide according to the equation shown below. C2H2(OH)2(CO2H)2 + 2KOH Æ C2H2(OH)2(CO2K)2 + 2H2O tartaric acid potassium tartarate A test analysis showed that 11.3 g of potassium tartarate was formed when 9.0 g of impure tartaric acid were used. Calculate the percentage purity of tartaric acid. [3] (b) All hydrocarbons undergo complete combustion to form carbon dioxide and water only. A 20.0 cm 3 sample of a hydrocarbon of formula C xH4 required 60.0 cm3 of oxygen for complete combustion. If both volumes are measured at r.t.p., what is the value of x? [2] [Total marks: 6] OH OH C C CO 2H HO2C H H

2011 End-of-Year Examination Secondary Three 6 Nanyang Girls’ High School Setters: GB/AS/ET Chemistry /II A4 (a) (i) Write the chemical formula for A, B, C and M. A ………………………………..………… B ………………………………..………… C ………………………………..………… M ………………………………..………… [2] (ii) Give the ionic equation, including the state symbols, for the formation of the dirty green precipitate. ....................................................................................................................... [2] (b) A colourless solution is suspected to contain either aluminium or lead(II) ions. Describe a chemical test which can be used to identify the metal ions present in the colourless solution and describe the expected observations. ............................................................................................................................... ....................................................................................................