JPJC 2025 H2 Chemistry WA1

© Jurong Pioneer Junior College [Turn Over JURONG PIONEER JUNIOR COLLEGE 2025 JC1 H2 WA1 (9476) REVISION PAPER 2 Instructions: You are advised to complete this practice in one sitting under examination conditions (i.e. timed conditions, quiet and undisturbed, with no reference to materials). Upon completion, mark your work against the solutions to gauge your level of competency. You will need writing materials (including 2B pencil), calculator and a Data Booklet. Name : __________________________________ Lack 3sf in final ans Class : 26S n Missing/wrong units in final ans Date : __________________ Final score 30 Duration: 55 minutes INSTRUCTIONS TO CANDIDATES  Answer ALL questions for Section A in the space provided. Section B is optional.  Do not use an erasable pen. Do not use correction fluid or tape.  All numerical answers should be given to 3 significant figures, unless otherwise stated.  A Data Booklet is provided.

2 © Jurong Pioneer Junior College 9476/J1 WA1 Revision Paper 2/2026 SECTION A (25 marks): Compulsory 1 (a) Explain the increasing trend in atomic radius of the elements down the group. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… [2] (b) The element selenium is in the same group as sulfur in the Periodic Table. (i) Write the electronic configuration of a selenium atom. 1s2 2s2 2p6 ……………………………………….. [1] (ii) Write an equation, with state symbols, to show the first ionisation energy of selenium. ……………………………………………………………………………………… [1] (iii) Explain why the first ionisation energy of Se is smaller in magnitude than that of arsenic (As). ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… [1] (c) The third to eighth ionisation energies for element A are shown in Table 1.1. Table 1.1 3rd 4th 5th 6th 7th 8th ionisation energy / kJ mol1 5320 7450 11 000 13 300 71 000 84 100 Use Table 1.1 to deduce the group of the Periodic Table that A belongs to. Explain your answer. group number ………. explanation ……………………………………………………………………………….. ……………………………………………………………………………………………… ……………………………………………………………………………………………… [2] [Total: 7]

3 © Jurong Pioneer Junior College 9476/J1 WA Revision Paper 2/2026 [Turn Over 2 (a) Compound B is a hydrocarbon with the formula of C xHy. A gaseous sample of B occupies 20 cm3 at 37 C and 100 kPa. The 20 cm 3 sample of B was completely burnt in 200 cm 3 oxygen gas (an excess). The final volume, measured at the same conditions as the gaseous sample, was 150 cm3. Under these conditions, water produced is in liquid state. Treating the remaining gaseous mixture with NaOH(aq), decreased the volume by 100 cm3. Use the data given to calculate the values of x and y. [2] (b) Another hydrocarbon, C2H4, reacts with MnO4, as shown in equation 1. equation 1 5C2H4 + 12MnO4 + 36H+  10CO2 + 12Mn2+ + 28H2O (i) Explain, with reference to oxidation numbers, why this reaction is a redox reaction. ……………………………………………………………………………………... ……………………………………………………………………………………... ……………………………………………………………………………………... [1] (ii) Write a half-equation to represent the conversion of C2H4 to CO2. ……………………………………………………………………………………... [1]

4 © Jurong Pioneer Junior College 9476/J1 WA1 Revision Paper 2/2026 (c) Sodium nitrite, NaNO 2, can be oxidised to sodium nitrate, NaNO 3, by reacting it with acidified potassium manganate(VII). The equation below shows the reaction between MnO4 and NO2. 2MnO4 + 5NO2 + 6H+ → 2Mn2+ + 5NO3 + 3H2O A 1.00 g sample of impure NaNO 2 was dissolved in water and the volume of the solution made up to 250 cm 3. A 25.0 cm 3 portion of this solution was found to react, in acidic medium, with 27.90 cm3 of 0.0140 mol dm3 KMnO4. (i) Calculate the mass of NaNO2 present in the sample. [2] (ii) Calculate the percentage purity of NaNO2 in the sample. [1] (iii) Draw a ‘dot-and-cross’ diagram of the NO3 ion in NaNO3. [1] [Total:8]

5 © Jurong Pioneer Junior College 9476/J1 WA Revision Paper 2/2026 [Turn Over 3 (a) A sample of an alloy containing rhodium (Rh) and iridium ( Ir) was analysed and three different types of atoms were identified; 103 45Rh , I 191 77 r and I 193 77 r . Table 3.1 shows information about the three types of atom found in the sample. Table 3.1 atom relative % abundance 103 45Rh 50.00 I 191 77 r 15.18 I 193 77 r 34.82 Use the data in Table 3.1 to calculate the relative atomic mass, Ar, of iridium, Ir, in this sample. Give your answer in two decimal places. [1] (b) Copper products are widely used in electrical grids and transportation. (i) Identify a highest energy orbital which contains electrons in a Cu + ion. Sketch the shape of this orbital on the axes provided below. identity of the highest energy orbital in Cu+ ion ……… [1] Tellurium, Te, is in the same group as oxygen in the Periodic Table. Te is mixed with copper to enhance its machinability. When fluorine gas is passed over Te, TeF4 is formed. Upon heating, TeF4 disproportionates to TeF6 and Te. (ii) Draw the dot-and-cross diagram of a TeF6 molecule. Use VSEPR theory to deduce the F-Te-F bond angle in TeF6. dot-and-cross diagram: F-Te-F bond angle: ………………………… [2] z y x

6 © Jurong Pioneer Junior College 9476/J1 WA1 Revision Paper 2/2026 (iii) Draw and name the shape of the TeF4 molecule. name of shape: ……………………………………… [2] (c) (i) Explain why the melting point of magnesium is higher than that of sodium. ……………………………………………………………………………………... ……………………………………………………………………………………... ……………………………………………………………………………………... ……………………………………………………………………………………... ……………………………………………………………………………………... ……………………………………………………………………………………... [2] (ii) Explain why MgF2 has a higher melting point than MgCl2. ……………………………………………………………………………………... ……………………………………………………………………………………... ……………………………………………………………………………………... ……………………………………………………………………………………... ……………………………………………………………………………………... ……………………………………………………………………………………... [2] [Total: 10]

7 © Jurong Pioneer Junior College 9476/J1 WA Revision Paper 2/2026 [Turn Over Section B (3 marks): Optional Bonus marks can be awarded if you score for Section B. You are advised to attempt Section B only after completing Section A. The question in this section is not compulsory. 4 Another way to reduce emissions is to use Si 3N4 to construct the pre-combustion chamber. The properties of Si3N4 makes it a perfect material for this purpose, as given below.  high melting point of 1900 C  insoluble in water  does not conduct electricity when molten Suggest the structure of and the type of bonding in Si 3N4. Show how you use the given properties to arrive at your answer. ……………………………………………………………………………………………........ ……………………………………………………………………………………………........ ……………………………………………………………………………………………........ ……………………………………………………………………………………………........ ……………………………………………………………………………………………........ ……………………………………………………………………………………………........ [3]