2024 XMS P2 PRELIM QP

3 XMSS/Chemistry/6092/02/Preliminary Examination 2024 Section A Answer all questions. 1 Choose from the following substances to answer the questions. A aluminium oxide, Al2O3 B carbon monoxide, CO C potassium dichromate(VI), K2Cr2O6 D ammonium nitrate, NH4NO3 E potassium manganate(VII), KMnO4 F fluorine, F2 G nitrogen dioxide, NO2 Use the letters A, B, C, D, E, F and G to answer the following questions. Each letter may be used once, more than once or not at all. Write the symbol for the substance which (a) is a neutral oxide. …………….. [1] (b) is able to oxidise iodide ions to iodine. …………….. [1] (c) produces an alkaline gas when warmed with sodium hydroxide. …………….. [1] (d) contains a transition metal with an oxidation state of +6. …………….. [1] (e) is soluble in rainwater, forming acid rain. …………….. [1] [Total: 5]

4 XMSS/Chemistry/6092/02/Preliminary Examination 2024 2 The reaction between ammonium perchlorate, NH 4ClO4, and aluminium metal is used to propel space shuttles. The reaction produces many substances such as steam and nitrogen gas. The equation shown below represents the reaction. ….. NH4ClO4 (s) + 10Al (s) → ….. Al2O3 (s) + 2AlCl3 (s) + ….. H2O (g) + 3N2 (g) (a) Balance and complete the equation by filling in the blanks. [1] (b) Calculate the oxidation state of chlorine in perchlorate ion, ClO4−. [2] (c) The reaction between aluminium and ammonium perchlorate is a redox reaction. State the role of aluminium in the redox reaction. Explain your reasoning , using changes in oxidation states of aluminium and chlorine. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [3] (d) Complete the energy profile diagram for this exothermic reaction. You diagram should show and label • ‘products’ of the reaction, • the activation energy, Ea, • the enthalpy change, H, of reaction. [3] [Total: 9] energy reactants progress of reaction

5 XMSS/Chemistry/6092/02/Preliminary Examination 2024 3 Proteins and PET are polymers made by condensation polymerisation. (a) The diagram in Fig. 3.1 shows the structure of a section of protein. Fig. 3.1 (i) Draw a ‘dot-and-cross’ diagram of the molecule that is removed during the polymerisation of proteins. Show outer electrons only. [2] (ii) Proteins are polyamides. Name one other example of a polyamide. ……………………………………………………………………………………. [1] (b) PET is a polymer used to make plastic bottles. The diagram in Fig. 3.2 shows the structure of PET. Fig. 3.2 (i) Name the linkage present in PET. ……………………………………………………………………………………. [1] (ii) Draw the structure of one of the monomer