ACSI 2020 Y6 Prelim Paper 1 QP

Additional materials: Multiple choice answer sheet Soft clean eraser Soft pencil (type 2B recommended) INSTRUCTIONS TO CANDIDATES Do not open this booklet until you are told to do so. Shade your Candidate number on the multiple choice answer sheet provided. There are forty questions in this paper. Answer all the 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. INFORMATION FOR CANDIDATES 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 booklet. A copy of the periodic table is provided for reference on Page 2 of the examination paper. Calculators are not allowed to be used in this paper. Anglo-Chinese School (Independent) YEAR 6 INTERNATIONAL BACCALAUREATE DIPLOMA PROGRAMME CHEMISTRY HIGHER LEVEL PAPER 1 Monday 14 September 2020 1 hour This question paper consists of 19 printed pages, including the cover page.

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3 1. Which compound has the greatest percentage by mass of nitrogen atoms? A. N2H4 B. NH3 C. N2O4 D. NaNO3 2. What is the sum of the coefficients when the equation is balanced? _____ C6H14 (g) + ____O2 (g) → ____CO (g) + ____H2O (l) A. 30 B. 39 C. 41 D. 54 3. What is the total number of electrons in all the s orbitals found in Cu+? A. 0 B. 1 C. 5 D. 6

4 4. Which electron transition absorbs radiation with the shortest wavelength? 5. The first seven successive ionisation energies (in kJ mol −1) of an atom of element J are given below: 1020 1950 2730 4580 6020 12300 15400 Which of the following statements about element J is correct? A. It has a valence shell electronic configuration of ns2 np4. B. Its atomic radius is larger than its ionic radius. C. It forms a covalent chloride that has a trigonal pyramidal shape. D. It forms an ionic compound with sodium in a 1:1 mole ratio. 6. Which compound has the shortest C to O bond? A. CH3CHO B. CH3COOH C. CO2 D. CO

5 7. Which species has a molecular geometry that is different from the CO32− ion? A. BF3 B. PF3 C. SO3 D. NO3 − 8. Which pair of molecules can form intermolecular hydrogen bonding with each other? A. CH4 and HF B. CH3OCH3 and CF4 C. CH3OH and H2O D. CH4 and H2O 9. Which of the following information about the specified central atom is correct? Atom Number of electron domains about one central atom Molecular geometry Hybridisation A. C in C2F2 2 linear sp B. C in C2H6 4 square planar sp3 C. N in NH3 3 trigonal pyramidal sp3 D. O in H2O 4 bent sp2

6 10. Which species have resonance structures? I. azide ion, N3 − II. carbon dioxide, CO2 III. benzene, C6H6 A. I and II only B. I and III only C. II and III only D. I, II and III 11. The graph below shows the variation in the melting points for the atoms of eight consecutive elements with atomic number below 20 in period 2 and 3 of the Periodic Table. Which statement is correct? A. Element E does not conduct electricity. B. Element D forms an acidic oxide. C. Element H forms covalent oxides with oxidation numbers of +4 and +6 respectively. D. Element C is a gas which is chemically inert at room temperature. melting point / K atomic mass

7 12. Which pair of elements shows the greatest difference in electronegativity? A. Na and S B. Li and I C. Mg and O D. Cs and F 13. EDTA4– (aq) solution is added dropwise until in excess to a solution of [CrC l2(H2O)4]+. The equilibrium constant for this reaction is greater than 1 and the equation for the reaction is as shown below. [CrCl2(H2O)4]+ (aq) + EDTA4− (aq) ⇌ [Cr(EDTA)]− (aq) + 2Cl− (aq) + 4H2O (l) Which of the following statements about the above reaction is correct? A. There is change in coordination number of the complex from 6 to 1. B. EDTA4− is a weaker ligand than Cl− ions. C. Both [CrCl2(H2O)4]+ and [Cr(EDTA)]− are octahedral complexes. D. It is a redox reaction. 14. Which equation correctly represents the standard enthalpy change of formation of a compound? A. 2C (s) + 3H2 (g) + 1 2 O2 (g) → C2H5OH (l) B. 2H2 (g) + O2 (g) → 2H2O (l) C. Na (s) + Cl (g) → NaCl (s) D. C (g) + O2 (g) → CO2 (g)

8 15. Using the equations below: C (s) + 1 2 O2 (g) → CO (g) ∆Hf = −110 kJ 2Cr (s) + 3 2 O2 (g) → Cr2O3 (s) ∆Hf = −1120 kJ what is the enthalpy change, ∆H (in kJ), for the following reaction? Cr2O3 (s) + 3C (s) → 2Cr (s) + 3CO (g) A. −110 − 1120 B. −110 + 1120 C. 3(−110) − 1120 D. 3(−110) + 1120 16. What are the correct signs for the enthalpy and entropy changes associated with the change below? CO2 (s) → CO2 (g) ∆H ∆S A. + − B. + + C. − − D. − +

9 17. A Born-Haber cycle involving a metal chloride, MCl2, is given below: Which of the following correctly describes the energy changes? ∆H2 ∆H5 ∆H6 A. atomisation hydration solution B. bond enthalpy hydration lattice energy C. atomisation solution hydration D. bond enthalpy solution lattice energy ∆H5 ∆H1 ∆H2 ∆H3 ∆H4 ∆H6 M (s) + Cl2 (g) MCl2 (aq) MCl2 (s) M (g) + Cl2 (g) M (g) + 2Cl (g) M2+ (g) + 2Cl− (g) 0

10 18. Which change does not increase the initial rate of reaction when MgCO 3 (s) is added to excess HCl (aq)? MgCO3 (s) + 2HCl (aq) → MgCl2 (aq) + H2O (l) + CO2 (g) A. A decrease in the size of the MgCO3 (s) particles B. An increase in the temperature of the reaction mixture C. An increase in the concentration of HCl (aq) D. Addition of deionised water into the reaction mixture 19. Which experimental methods could be used to observe the progress of the following reaction? Cr2O72– (aq) + 6I– (aq) + 14H+ (aq) → 2Cr3+ (aq) + 3I2 (aq) + 7H2O (l) I. Change in colour II. Change in mass III. Change in electrical conductivity A. I and II only B. I and III only C. II and III only D. I, II and III 20. The rate expression for the reaction A (g) + 2B (g) → 3Z (g) is rate = k [A]0 [B]2 By which factor will the rate of reaction increase when the concentrations of A and B are both increased by a factor of 3? A. 3 B. 6 C. 9 D. 12