2020 JC2 H1 Chem Prelim Paper 2 (QP) 16 Aug

Tampines Meridian Junior College 2020 JC2 Prelim H1 Chemistry CANDIDATE NAME CIVICS GROUP __________________________________________________________________________________ H1 CHEMISTRY 8873/02 Paper 2 Structured Questions 15 September 2020 2 hours Candidates answer on the Question Paper Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name and Civics Group in the spaces at the top of this page. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. Section A Answer all the questions. Section B Answer one question only. The number of marks is given in brackets [ ] at the end of each question or part question. __________________________________________________________________________________ This document consists of 28 printed pages including 1 blank page. For Examiner’s Use Paper 1 MCQ / 30 Paper 2 Q1 / 14 Q2 / 11 Q3 / 10 Q4 / 13 Q5 / 12 Q6 / 20 Q7 / 20 / 80 Percentage / 100 Grade TAMPINES MERIDIAN JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION

2 Tampines Meridian Junior College 2020 JC2 Prelim H1 Chemistry Section A Answer all the questions in this section in the spaces provided. 1 (a) Sulfur is in the p block while calcium is in the s block of the Periodic Table. (i) State the electronic configuration of a Ca+ ion. Ca+ : ………..………………..………… [1] (ii) Draw and label the shape of a 3px orbital. [1] (iii) Beams of 40Ca+ ions and 32S2– ions were passed through an electric field. It was observed that a beam of 40Ca+ ions gives an angle of deflection of 2 as shown below. Sketch the path of the beam of 32S2– ions in the diagram above. Include the angle of deflection in your answer. [2] 40Ca+ source – + 2

3 Tampines Meridian Junior College 2020 JC2 Prelim H1 Chemistry (b) The diagram below gives the ionisation energies of five consecutive unknown elements J to N with atomic numbers less than 20. (i) Explain the increasing trend of the 1st ionisation energies from elements J to L. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..………………………………………………………… [2] (ii) State, with reasoning, which Group element M belongs to. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..………………………………………………………… [2] 0 1000 2000 3000 4000 5000 6000 7000 8000 V W X Y Z Element Ionisation Energy / kJ mol-1 1st ionisation energies 2nd ionisation energies 3rd ionisation energies element ionisation energy / kJ mol1 J K L M N

4 Tampines Meridian Junior College 2020 JC2 Prelim H1 Chemistry (c) The oxides, Na 2O, MgO, A l2O3, SiO 2, P 4O10 and SO 3, differ considerably in their chemical properties. (i) Describe the difference in the acid-base nature of these oxides with reference to the chemical bonding in these oxides. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..………………………………………………………… [2] (ii) Write an equation for the reaction of Al2O3 with aqueous sodium hydroxide. ……...…..………………..………………………………………………………… [1] (d) The table below shows some physical properties of oxides of elements W, X, Y and Z. formula of oxide melting point / oC appearance at room temperature conductivity in molten state WO2 1700 White solid None X2O 0 Colourless liquid None YO 2850 White solid Good ZO2 -78 Colourless gas None (i) Explain the difference in melting points between WO2 and ZO2 in terms of structure and bonding. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..………………………………………………………… [2]

5 Tampines Meridian Junior College 2020 JC2 Prelim H1 Chemistry (ii) When a positively charged poly(ethene) rod is held near X2O which is released from a burette in a slow steady stream, the stream is deflected towards the rod. Explain why the stream experiences a deflection. ……...…..………………..……………………………………………………………. ……...…..………………..………………………………………………………… [1] [Total: 14] positively charged rod stream of X2O beaker

6 Tampines Meridian Junior College 2020 JC2 Prelim H1 Chemistry 2 Cinnamon is used as a condiment in various cuisines. The aroma of cinnamon is derived from its principal component, cinnamaldehyde, as well as numerous other constituents, including terpineol. (a) Cinnamaldehyde, C6H5CH=CHCHO is able to exhibit cis-trans isomerism. Explain why cinnamaldehyde exhibits cis-trans isomerism and draw the structure of the cis-trans isomers. ……...…..………………..…………………………………………………………………….. ……...…..………………..…………………………………………………………………….. ……...…..………………..…………………………………………………………………. [3] (b) Describe the bonding in C=C of C6H5CH=CHCHO in terms of orbital overlap. ……...…..………………..…………………………………………………………………….. ……...…..………………..…………………………………………………………………….. ……...…..………………..…………………………………………………………………….. ……...…..………………..…………………………………………………………………….. ……...…..………………..…………………………………………………………………. [2]

7 Tampines Meridian Junior College 2020 JC2 Prelim H1 Chemistry (c) Cinnamaldehyde can be converted into the following compounds. State the reagents and conditions required for reactions I and II. I: ………..………………..……………………………….. II: ………..………………..………………………………. [2] (d) Terpineol can be synthesised from a two-stage process as shown below. (i) State the reagents, conditions and types of reaction for stages 1 and 2. Stage Reagents and conditions Type of reaction 1 2 [2]

8 Tampines Meridian Junior College 2020 JC2 Prelim H1 Chemistry (ii) Suggest a suitable chemical test to distinguish terpineol from Compound L, an isomer of terpineol. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..………………………………………………………… [2] [Total: 11]

9 Tampines Meridian Junior College 2020 JC2 Prelim H1 Chemistry 3 Synthetic polymers are macromolecules which have many uses. (a) Styrene-Butadiene Rubber (SBR) is a synthetic copolymer that is synthesised from two different monomers, styrene and 1 -3-butadiene. It is durable and has good abrasion resistance allowing it to be used for the soles of shoes and tyres. (i) State the type of polymerisation used to form SBR. Substantiate your answers with two reasons. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..……………………………………………………………. ……...…..………………..………………………………………………………… [2] (ii) Assuming that the monomers join together in a 1:1 ratio, draw a repeating unit of the styrene-butadiene rubber. [1] (iii) The styrene / butadiene ratio influences the properties of the SBR polymer. With high styrene content, the rubbers are signifi