Questions Q1. The first ionization energies, in kj mol -1, of four elements with consecutive atomic numbers are shown below. A 1680 B 2080 C 496 D 738

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1 Questions Q1. The first ionization energies, in kj mol -1, of four elements with consecutive atomic numbers are shown below (a) Which element could be an inert gas? (b) Which element could be X in a covalent compound with formula HX? (c) Which element could be Y in an ionic compound with formula YH 2? (Total for question = 3 marks)

2 Q2. The graph below shows the second ionization energy of a series of elements with consecutive atomic numbers. Which element could be lithium? Q3. Oxygen can be prepared using several different reactions. Which of those given below has the highest atom economy by mass? Q4.

3 Which of the following processes has the highest atom economy? Making poly(ethene) from ethene. Making ethene from eicosane, 20 H 42. Making chloromethane from methane. Making magnesium chloride from magnesium and hydrochloric acid. Q5. How many molecules are present in 16 g of oxygen gas, O 2 (g)? [vogadro constant = mol 1 ] Q6. The graph below shows the boiling temperatures of the hydrides of Group 7. (a) (i) Identify the type of intermolecular force that gives rise to the unusually high

4 boiling temperature of hydrogen fluoride. (ii) State and explain whether the electronegativity of fluorine is greater than, similar to or less than, that of bromine. Hence explain why hydrogen fluoride can form the type of intermolecular force named in (a)(i) but hydrogen bromide cannot. (3) (iii) Use the graph to predict what the boiling temperature of hydrogen fluoride would be without the presence of the type of intermolecular force named in (a)(i). (b) Propanone, H 3 OH 3, is a useful solvent for cleaning glassware in laboratories. (i) Why is propanone able to dissolve a wide range of substances? (ii) Propanone can be used to remove both water and octane from glassware. For each of these substances, identify the strongest intermolecular force formed with propanone and the feature of the propanone molecule involved. (2) Water

5 Octane (Total for question = 8 marks) Q7. For parts (a) and (b), use your knowledge of intermolecular forces to predict the compound with the highest boiling temperature. (Total for question = 2 marks) Q8. This question is about bond angles Select, from to above, the most likely value for the bond angle of (a) HH in methane, H 4.

6 (b) FSF in sulfur hexafluoride, SF 6. (c) FOF in oxygen difluoride, OF 2. (Total for question = 3 marks) Q9. Which of the following covalent bonds is the shortest? H F H l H r H I Q10.

7 Which of the following has dipole-dipole interactions between its molecules, but no hydrogen bonding? Methane, H 4 Methanol, H 3 OH mmonia, NH 3 Hydrogen iodide, HI Q11. (a) Explain how the atoms are held together by the covalent bond in a molecule of hydrogen. (b) raw the dot and cross diagrams for (i) methane, H 4 (ii) ethene, H 2 H 2 (iii) nitrogen, N 2 (iv) the ammonium ion, NH 4 + (c) Silicon exists in a giant covalent lattice. (i) The electrical conductivity of pure silicon is very low. Explain why this is so in terms of the bonding. (2)

8 (ii) Explain the high melting temperature of silicon in terms of the bonding. (2) (Total for question = 9 marks) Q12. This question is about the reaction between sodium carbonate solution and dilute nitric acid. Na 2 O 3 (aq) + 2HNO 3 (aq) 2NaNO 3 (aq) + O 2 (g) + H 2 O(l) (a) What is the ionic equation for this reaction? Na 2 O 3 (aq) + 2H + (aq) 2Na + (aq) + O 2 (g) + H 2 O(l) Na + (aq) + NaNO 3 (aq) + 2H + (aq) O 2 (g) + H 2 O(l) + 2HNO 3 (aq) + O 2 (g) + H 2 O(l) (b) What is the volume of carbon dioxide produced from the complete reaction of 0.10 mol of nitric acid at room temperature and pressure? [1 mol of any gas occupies 24 dm 3 at room temperature and pressure.] 1.2 dm dm dm dm 3 (c) What volume of sodium carbonate solution of concentration mol dm 3, would be

9 needed to completely react with 25.0 cm 3 of nitric acid of concentration mol dm 3? 6.25 cm cm cm cm 3 Q13. When 0.1 mol of aqueous potassium hydroxide was added to 0.1 mol of nitric acid, 5200 J were transferred to the surroundings. What is the enthalpy change, in kj mol 1, for this reaction? KOH(aq) + HNO 3 (aq) KNO 3 (aq) + H 2 O(l) Q14. Hydrogen and oxygen react according to the following equation. If all volumes are measured at 110 and one atmosphere pressure, the volume of steam produced after 50 cm 3 of hydrogen react completely with 25 cm 3 of oxygen is 25 cm 3 50 cm 3 75 cm 3

10 100 cm 3 Q15. Which of these is likely to be the best solvent for cyclohexanol? H 2 O(l) H 3 OH 3 (l) Nal(aq) H 3 H 2 H 2 H 2 H 2 H 3 (l) Q16. Sodium and sodium chloride can both be good conductors of electricity. Under what conditions do these substances conduct electricity? ompare the method of conductivity in each case. (3) Q17. Which of the following molecules has the highest melting temperature?

11 Q18. (i) omplete the dot and cross diagram for chloric(i) acid (HOl). Use a dot ( ) to represent the hydrogen electron, circles (o) to represent the oxygen electrons and crosses ( ) to represent the chlorine electrons. Show the outer electrons only, but include non-bonding electrons. (2) *(ii) Predict the bond angle in chloric(i) acid. Explain your answer fully. (5) ond angle =...

12 Q19. raw a diagram to show the bonding in the single product of the reaction between F 3 and NF 3. Identify the type of bond that forms between these two molecules. (2) (Total for question = 2 marks) Q20. Which of the following contains a dative covalent bond? N 2 NH 3 NH 2 NH 4 +

13 Q21. Sodium and chlorine react together to produce sodium chloride. The bonding in the product is different from that in both of the reactants. Evidence for the type of bonding present can be obtained in a number of different ways. Sodium chloride is ionically bonded. What is meant by the term ionic bond? Q22. Which of the following is not a disproportionation reaction? l 2 + 2OH l + lo + H 2 O u 2 O + H 2 SO 4 uso 4 + u + H 2 O 3IO 2I + IO 3 + u + 4HNO 3 u(no 3 ) 2 + 2H 2 O + 2NO 2 Q23. Which one of these reactions is not a disproportionation reaction? 2H 2 O 2 (aq) O 2 (g) + 2H 2 O(l) S 2 O 2 3 (aq) + 2H + (aq) SO 2 (g) + S(s) + H 2 O(l) l 2 (aq) + 2r (aq) 2l (aq) + r 2 (aq) 2u + (aq) u(s) + u 2+ (aq)

14 Q24. Which of these has a dative covalent bond? NH 3 OH H 2 O H 3 O + Q25. This question is about the use of mass spectrometers. (a) omplete the mass spectrum below for a sample of bromine gas that contains approximately half 79 r isotope and half 81 r isotope. (4) (b) alculate the relative atomic mass of bromine for a sample which was found to contain 47.0% 79 r and 53.0% 81 r. Give your answer to three significant figures. (c) What would be the effect, if any, on the m/e value of the peak if the ion detected had lost two electrons rather than one electron? (2)

15 Q26. Which of the following has the largest ionic radius? S 2 l K + a 2+ (Total for Question = 1 mark) Q27. In which of the following electronic configurations are only two of the electrons unpaired? 1s 2 2s 2 1s 2 2s 2 2p 3 1s 2 2s 2 2p 4 1s 2 2s 2 2p 5 Q28. Which of the following represents the electronic structure of a nitrogen atom?

16 Q29. The electronic structures of four elements are given below. Which of these elements has the highest first ionization energy? Q30. drop of sodium manganate(vii) solution is placed at the centre of a piece of moist filter paper on a microscope slide. The ends of the paper are clipped to a 30 V power supply. fter a few minutes, a purple colour has moved towards the positive terminal. a purple colour has moved towards the negative terminal. an orange colour has moved towards the positive terminal. an orange colour has moved towards the negative terminal. (Total for Question = 1 mark)

17 Q31. The equation for the reaction of chlorine with water is: l 2 (aq) + H 2 O(l) HOl(aq) + Hl(aq) y referring to the relevant oxidation numbers, explain why this is a disproportionation reaction. (3) Q32. The first ionization energy of each of the elements from neon to argon is shown on the graph below. The first ionization energy of potassium has been omitted.

18 (a) efine the term first ionization energy. (3) (b) Explain why, in moving from Na to r, the general trend is for the first ionization energy to increase. (3)

19 (c) Explain why the first ionization energy decreases from P to S. (2) (d) Estimate the value of the first ionization energy of potassium, K, and write your answer below.... kj mol 1 (Total for Question = 9 marks) Q33. Which of the following is the correct order of increasing melting temperature of elements of Period 3? Na, Mg, l, Si Na, Mg, Si, l Si, Na, Mg, l Si, l, Mg, Na

20 Q34. What is the percentage by mass of nitrogen in ammonium nitrate, NH 4 NO 3? [Molar masses/g mol 1 : N = 14.0; H = 1.0; O = 16.0] 14.0% 17.5% 28.0% 35.0% Q35. s Group 2 is descended the solubility of hydroxides and of sulfates increases. the solubility of hydroxides increases and of sulfates decreases. the solubility of hydroxides decreases and of sulfates increases. the solubility of hydroxides and of sulfates decreases. Q36. Which of the following could not be an element in Group 2? n element with an oxide which forms a solution of ph 10. n element with an insoluble sulfate. n element with a chloride which is liquid at room temperature. n element with a carbonate which decomposes on heating. Q37.

21 The carbonates of Group 2 in the Periodic Table decompose on heating to form the corresponding metal oxide and carbon dioxide. general equation for the reaction is The thermal stability of these carbonates can be compared in the laboratory using the apparatus in the diagram below. The test tube on the left contains a sample of a metal carbonate and the tube on the right contains limewater. (a) (i) State the measurement that you would make in this experiment. (ii) Suggest three ways to make sure that, when carrying out this experiment, the thermal stabilities of the different carbonates are compared fairly (b) (i) State the trend in the thermal stability of the metal carbonates as the group is descended. (3)

22 *(ii) Explain this trend in stability. (3) (Total for question = 8 marks) Q38. The diagram below is taken from a student's examination paper. It shows the hydrogen bonding between two water molecules. Identify the error in the diagram. The H O H bond angle within each water molecule should be 90. There should only be one lone pair of electrons on each oxygen atom. The O H O bond angle between the water molecules should be 180. The hydrogen atoms should be and the oxygen atoms should be +. (Total for Question = 1 mark)

23 Q39. Which of the following molecules is polar? arbon dioxide, O 2 Silicon tetrachloride, Sil 4 mmonia, NH 3 oron trifluoride, F 3 Q40. The bond angle in beryllium chloride, el 2, is most likely to be Q41. Which of the following properties decreases on descending Group 2 of the Periodic Table? Solubility of the sulfates. Solubility of the hydroxides. Reactivity of the elements.

24 Ionic character of the oxides. Q42. In which of the following reactions is sulfuric(iv) acid, H 2 SO 3, acting as an oxidizing agent? H 2 SO 3 + H 2 O H 3 O + + H 2 SO 3 SO 2 + H 2 O H 2 SO 3 + 2Fel 3 + H 2 O 2Fel 2 + H 2 SO 4 + 2Hl H 2 SO 3 + 2H2S 3H 2 O + 3S Q43. Which intermolecular forces exist between molecules of ethoxyethane? Instantaneous dipole induced dipole only Permanent dipole permanent dipole only Instantaneous dipole induced dipole and hydrogen bonds Instantaneous dipole induced dipole and permanent dipole permanent dipole

25 Q44. The difference in boiling temperature between methane (T b = 109 K) and ethane (T b = 185 K) is best explained by the different numbers of protons. electrons. covalent bonds. hydrogen bonds. Q45. The boiling temperatures of fluorine and two of its compounds are given below. (a) molecule of F 2 has 18 electrons. Which intermolecular force depends to a large extent on the number of electrons in the molecule? (b) alculate the number of electrons in a molecule of H 3 F. (c) Explain why the boiling temperature of H 3 F is greater than that of F 2, referring to the intermolecular forces present. (d) Explain why the boiling temperature of HF is the highest in the series.

26 (2) (e) Explain why the values of the boiling temperatures for l 2, H 3 l and Hl do not follow the same trend as F 2, H 3 F and HF. (Total for Question = 6 marks) Q46. hlorine has two isotopes with relative isotopic mass 35 and 37. Four m/z values are given below. Which will occur in a mass spectrum of chlorine gas, l 2, from an ion with a single positive charge? Q47. Metals are good conductors of heat and electricity and usually have high melting temperatures and boiling temperatures. (a) (i) escribe the structure of a metal. (2)

27 (ii) escribe the bonding in a metal. (2) (b) Explain why the melting temperature of magnesium (650 ) is much higher than that of sodium (98 ). (3) (c) Explain how metals conduct electricity. (2) (Total for Question = 9 marks) Q g of magnesium ribbon reacted with exactly 22.2 cm 3 of hydrochloric acid of concentration 1.50 mol dm 3.

28 Powered by TPF ( 400 cm 3 of hydrogen gas was formed, the volume being measured at room temperature and pressure. In the calculations that follow, use the following molar masses: Mg = 24.0 g mol 1 l = 35.5 g mol 1 (a) alculate the amount (in moles) of magnesium used. (b) alculate the amount (in moles) of hydrochloric acid used. (c) alculate the amount (in moles) of hydrogen produced. [Molar volume of any gas at room temperature and pressure = cm 3 mol 1 ] (d) Show that the calculated amounts of magnesium, hydrochloric acid and hydrogen are consistent with the following equation for the reaction (e) alculate the maximum mass of magnesium chloride that would be formed in this reaction. Give your answer to three significant figures. (3) (Total for Question = 7 marks)