2021 SASS 4E Chem MYE Error Analysis

_______________________________________________________________________________________________________________________________________________________________________________________ Page 1 ST ANDREW’S SECONDARY SCHOOL NAME CLASS DATE CHEMISTRY 6092 Mid-Year Examination 2021 Error Analysis 1 2 3 4 5 6 7 8 9 10 Record your answers here 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 1 Which statement about nitrogen atoms is not correct? [ACSB’17] A All nitrogen atoms have the same atomic number. B All nitrogen atoms have the same chemical properties. C All nitrogen atoms have the same electronic configuration. D All nitrogen atoms have the same mass number. 2 The table below shows the number of neutrons and electrons in four particles. Particle Number of neutrons Number of electrons P 18 8 Q+ 12 10 R2- 16 10 S 22 18 Which particle is an isotope of P? [ACSB’17] A Q B R C S D None of the above

_______________________________________________________________________________________________________________________________________________________________________________________ Page 2 3 A molecule consists of three types of atoms, P, X and Y. If P is phosphorous, what could X and Y be? [ACSB’17] X Y A Al H B N Cl C O H D Si Cl 4 The diagram shows part of the structure of a salt, XY. Which statement is correct? [ACSB’17] A Each Y- ion is bonded to five X+ ions. B Each X atom is bonded six Y atoms. C The ratio of X+ to Y- is 1:1. D The structure shown is able to conduct electricity. X P X P X P Y Y Y Y Y Y Anglo-Chinese School (Barker Road) Preliminary Examination 2017 Secondary 4 Express Chemistry (5073) Page 5 of 17 8. The diagram shows part of the structure of a salt, XY. Which statement is correct? A Each Y ion is bonded to five X+ ions. B Each X atom is bonded to six Y atoms. C The ratio of X+ to Y is 1 : 1. D The structure shown is able to conduct electricity. 9. Sodium carbonate is added to 1.0 mol/dm3 of excess ethanoic acid, hydrochloric acid and sulfuric acid separately. Which correctly matches the graph to the acid used in each reaction? sulfuric acid hydrochloric acid ethanoic acid A 1 2 4 B 1 4 3 C 2 3 4 D 2 4 3

_______________________________________________________________________________________________________________________________________________________________________________________ Page 3 5 Sodium carbonate is added to separate solutions of excess 1.0mol/dm3 ethanoic acid, hydrochloric acid and sulfuric acid. Which correctly matches the graph to the acid used in each reaction? [ACSB’17] Ethanoic acid Hydrochloric acid Sulfuric acid A 4 2 1 B 3 4 1 C 4 3 2 D 3 4 2 6 Carbon disulfide, CS2 is a simple covalent compound used in the manufacturing of polymers and fibres. A student made the following statements: