2025 YIJC H1 Chem Prelim P2 (for exchange)

©YIJC 8873/02/JC2/PE/2025 [Turn over YISHUN INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 1 CANDIDATE NAME CG H1 GROUP 1 / 2 CHEMISTRY Paper 2 Structured Questions Candidates answer on the Question Paper. Additional Materials: Data Booklet 8873/02 1 September 2025 2 hours READ THESE INSTRUCTIONS FIRST This document consists of 26 printed pages and 2 blank pages. For Examiner’s Use Section A 1 / 11 2 / 9 3 / 11 4 / 12 5 / 5 6 / 12 Section B 7 or 8 / 20 Penalty units significant figures Total / 80 Write your name and class in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions. Section B Answer one question. The use of an approved scientific calculator is expected, where appropriate. The number of marks is given in brackets [ ] at the end of each question or part question.

2 ©YIJC 8873/02/JC2/PE/2025 Section A Answer all the questions in this section in the spaces provided. 1 (a) Elements A, B and C are three consecutive elements from Period 3 of the Periodic Table. Element B has the successive ionisation energies as shown in Table 1.1. Table 1.1 ionisation energies / kJ mol–1 1st 2nd 3rd 4th 5th 6th 7th 8th 577 1820 2740 11600 14800 18400 23300 27400 (i) Explain how the data shows that element B belongs to Group 13. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. …………………………………………………………………………………………………….[1] (ii) Hence, write the full electronic configuration of B. 1s2………………………………………………………………………………………………...[1] (iii) Explain why the first ionisation energy of element B is lower than the first ionisation energy of elements A and C. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. …………………………………………………………………………………………………….[3]

3 ©YIJC 8873/02/JC2/PE/2025 [Turn over (b) Oxygen and chlorine react with phosphorus to form phosphorus( V) oxide and phosphorus(V) chloride respectively. Describe the reactions when phosphorus( V) oxide and phosphorus( V) chloride are added separately to two separate beakers of water. In each case, give appropriate equations and state the likely pH of the resulting solution. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ……………………………………………………………………………………………………………[4] (c) Group 1 elements are known as alkali metals because they are able to form alkaline solutions in water. Table 1.2 shows how some Group 1 elements react with water. Table 1.2 Group 1 element description of the reaction with water Li fizzes steadily, gradually disappears Na fizzes rapidly, melts into a ball and disappears quickly K ignites with sparks and lilac flame, disappears very quickly (i) Write an equation for the reaction between sodium and water. ..........................................................................................................................................[1] (ii) Explain why the reaction of Group 1 metals and water becomes more vigorous down the group. …………………………………………………………………………………………………….… …………………………………………………………………………………………………….[1] [Total: 11]

4 ©YIJC 8873/02/JC2/PE/2025 2 (a) In 1933, British chemists accidentally discovered that subjecting ethene to high pressure in the presence of trace amounts of oxygen resulted in the formation of a soft, white solid. This solid was identified as poly(ethene), marking the beginning of a maj or global polymer industry. Depending on the reaction condi tions, the polymerisation of ethene can produce either low-density poly(ethene) (LDPE) or high -density poly(ethene) (HDPE), each with distinct structural and physical properties. (i) Sketch the structures of LDPE and HDPE using as a simplified representation of the polymer chain. LDPE HDPE [2] (ii) Poly(ethene) can be used to make squeezable bottles. By considering the structure and properties of LDPE and HDPE, deduce which poly(ethene) is suitable as a material for squeezable bottles. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. …………………………………………………………………………………………………….[2]

5 ©YIJC 8873/02/JC2/PE/2025 [Turn over (b) In recent years, there have been concerns worldwide about the environmental impact of catastrophic oil spills caused by oil tanker accidents at sea. Such oil spills can cause havoc to marine life and pose health hazards to the human population located in nearby coastal zones. Conventional techniques such as use of sponges are not adequate to solve the problem of massive oil spills. Sponges have high reusability but low efficiency in clearing oil from sea water as it soaks up liquid mechanically. Nanomaterials have emerged as a pot ential source of novel solution to this problem. One nanomaterial that offers huge promise is nanostructured organoclays. Each particle of nanostructured organoclay has a diameter of about 300 nm and is known to have low polarity. (i) Explain why nanostructured organoclay cannot be considered a nanoparticle. ………………………………………………………………………………………………………. …………………………………………………………………………………………………….[1] (ii) Give two reasons why nanostructured organoclay shows huge promise in solving the problem of oil spills. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. …………………………………………………………………………………………………….[2] (iii) Another material that can be used to remove oil spills is carbon nanotubes, which are formed when layers of graphene roll up. Draw the structure of graphene. [1] (iv) Carbon nanotubes can also be used in electronics, to make electrical wires and cables. Explain the property of carbon nanotubes that enables it to be used for such purposes. ………………………………………………………………………………………………………. …………………………………………………………………………………………………….[1] [Total: 9]

6 ©YIJC 8873/02/JC2/PE/2025 3 The combustion of sulfur-containing fossil fuels, such as coal, results in the formation of acidic oxides sulfur dioxide (SO2) and sulfur trioxide (SO3), which are significant atmospheric pollutants. To determine the sulfur content in a given coal sample, the following analytical procedure was carried out: • step 1 : A 4.0 kg sample of coal was subjected to complete combustion in a controlled environment. The combustion products were processed to isolate and collect the SO2 and SO3 from the exhaust gases. • step 2: The collected gas mixture containing SO2 and