Chem S3 EOY 2023 GESS Ans

GESS 3EXP CHEM EYE 2023 TKG Answers for 3EXP Chem EYE P1 2023 1. B 11. C 21. A 31. D 2. B 12. C 22. C 32. D 3. C 13. B 23. C 33. B 4. A 14. A 24. C 34. D 5. C 15. B 25. C 35. C 6. D 16. A 26. B 36. D 7. D 17. A 27. B 37. B 8. A 18. B 28. A 38. A 9. A 19. D 29. C 39. C 10. D 20. D 30. A 40. C Qn Ans Explanation 1. B 22.15 cm 3 is accurate to 2 decimal places. Burette should be used as it can record up to 2dp (nearest 0.05 cm 3). Beaker measures approximate volumes. Measuring cylinder measures to the nearest 0.5 cm3. Pipette is only accurate for fixed volumes up to 1dp. 2. B Concentrated sulfuric acid is used to dry acidic gases like sulfur dioxide. 3. C The apparatus shown is for the upward delivery gas collection method. Gas X must be less dense than air to be collected by an inverted gas jar. There is not enough information to deduce the solubility of gas X. 4. A Since solid Y is insoluble in ethanol, filtration can be used to easily separate them. The boiling points given are distractors. 5. C The diagram shows that the entire starting line has dissolved in the solvent and travelled up the chromatogram. This means that Megan did not use a pencil (which is insoluble in water) but instead used a pen (containing ink which is soluble in water).

GESS 3EXP CHEM EYE 2023 TKG 6. D Rf = 7 13 = 0.538 7. D Substance Z is a solid at 179 ºC and a gas at 232 ºC. For option D, substance Z will change from solid to liquid state at 194 ºC and change from liquid to gaseous state at 229 ºC. 8. A Protons and neutrons are found in the nucleus of an atom while electrons are found in the electron shells around the nucleus. 9. A I is correct as the innermost shell can only contain two electrons. II is incorrect as the second shell can contain up to eight electrons. III is incorrect as the electron pairs can be placed at any of the four sides of the atom. IV is incorrect as the electronic structure shown is for an ATOM of J, not an ion. The valence shell of atoms are not always fully-filled. 10. D From the chemical formula XO, we know that the two ions in this ionic compound are X2+ and O2-. Electrons are negatively charged. To form an oxide ion of 2- charge, oxygen atom must gain 2 electrons from an atom of X. Similarly, for X to become X2+ ion, each atom of X must lose 2 electrons. 11. C In A, F- has 10 electrons, Cl- has 18 electrons, and Br- has 36 electrons. In B, H+ has 0 electrons, He has 2 electrons, and N3- has 10 electrons. In C, K+ has 18 electrons, Ca2+ has 18 electrons, and P3- has 18 electrons. In D, Na+ has 10 electrons, Mg2+ has 10 electrons, and S2- has 18 electrons. 12. C Each oxygen atom contains 6 valence electrons. 2 of these are used for bonding with sulfur and 4 are not. Therefore, electrons not used for bonding = 4 + 2 inner shell electrons = 6 13. B Covalent bonds are formed between non-metallic elements. Metals and non-met