2021_MI_Prelim_P1_Ans

Class Adm No Candidate Name: This question paper consists of 14 printed pages and 2 blank pages. 2021 End-of-Year Examinations Pre-University 2 H1 CHEMISTRY 8873/01 Paper 1 Multiple Choice 22nd Sep 2021 1 hour Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not turn over this question paper until you are told to do so. Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and admission number in the spaces provided at the top of this page and on the Multiple Choice Answer Sheet provided. There are thirty questions on this paper. Answer ALL questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the Multiple Choice Answer Sheet provided. Read the instructions on the Multiple Choice Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this question paper. The use of an approved scientific calculator is expected, where appropriate. FOR EXAMINER’S USE TOTAL (30 marks)

2 1 Magnetite, Fe3O4, is an equimolar mixture of iron(II) oxide, FeO, and iron(III) oxide, Fe2O3. 3.48 g of magnetite is dissolved in excess dilute sulfuric acid. 25.0 cm3 of K2Cr2O7(aq) exactly oxidises the dissolved Fe2+ present according to the equation. Cr2O72- (aq) + 14H+ (aq) + 6Fe2+ (aq) → 2Cr3+ (aq) + 7H2O (l) + 6Fe3+ (aq) What is the concentration, in mol dm–3, of the K2Cr2O7(aq) used? A 0.01 B 0.05 C 0.10 D 0.20 2 What are the oxidation states of oxygen in the following compounds? O2 OF2 H2O2 A 0 -2 -1 B 0 +2 -1 C -2 -2 -2 D -2 +2 -2 3 An acidified solution of the salt KClO2 oxidises Ti3+(aq) to Tin+(aq) while the chlorine is reduced to C l(aq). When 0.00245 mol of KC lO2 reacted with 0.400 mol dm 3 Ti3+(aq), 24.50 cm 3 of Ti3+(aq) was needed for complete reaction. What is the value of n? A 1 B 2 C 3 D 4 4 An ion X2+ contains 24 protons. What is the electronic configuration of X2+? A 1s2 2s2 2p6 3s2 3p6 3d4 B 1s2 2s2 2p6 3s2 3p6 3d2 4s2 C 1s2 2s2 2p6 3s2 3p6 3d5 4s1 D 1s2 2s2 2p6 3s2 3p6 3d6 4s2

3 [Turn over 5 The table gives the successive ionisation energies for an element G. 1st 2nd 3rd 4th 5th 6th Ionisation energy / kJ mol1 750 1800 3700 5600 16000 20300 What is the formula of the chloride of G? A GCl B GCl2 C GCl3 D GCl4 6 Which of the following pairs of molecules have the same shape? A AlCl3 and PCl3 B SO3 and BF3 C NH3 and BCl3 D SO2 and CO2 7 Which of the following statements about graphite is incorrect? A All the bond angles in it are 120o.