Q1. The table below shows the boiling points of some hydrogen compounds formed by Group 6 elements. S H 2 O H 2. Boiling point / K

Transcription

1 Q1. The table below shows the boiling points of some hydrogen compounds formed by Group 6 elements. H O H S H Se H Te Boiling point / K (a) State the strongest type of intermolecular force in water and in hydrogen sulfide (H S). Water... Hydrogen sulfide (b) Draw a diagram to show how two molecules of water are attracted to each other by the type of intermolecular force you stated in part (a). Include partial charges and all lone pairs of electrons in your diagram. (c) Explain why the boiling point of water is much higher than the boiling point of hydrogen sulfide (d) Explain why the boiling points increase from H S to H Te (e) When H + ions react with H O molecules, H 3 O + ions are formed. Name the type of bond formed when H + ions react with H O molecules. Explain how this type of bond is formed in the H 3 O + ion. Type of bond... Explanation Page 1 of

2 (f) Sodium sulfide (Na S) has a melting point of 13 K. Predict the type of bonding in sodium sulfide and explain why its melting point is high. Type of bonding... Explanation (Total 13 marks) Q. At room temperature, both sodium metal and sodium chloride are crystalline solids which contain ions. (a) On the diagrams for sodium metal and sodium chloride below, mark the charge for each ion. (b) Explain how the ions are held together in solid sodium metal. Explain how the ions are held together in solid sodium chloride. (iii) The melting point of sodium chloride is much higher than that of sodium metal. What can be deduced from this information? Page of

3 (c) Compare the electrical conductivity of solid sodium metal with that of solid sodium chloride. Explain your answer. Comparison Explanation (d) Explain why sodium metal is malleable (can be hammered into shape) (e) Sodium chlorate(v), NaClO 3, contains 1.6% by mass of sodium, 33.3% by mass of chlorine and 45.1% by mass of oxygen. Use the above data to show that the empirical formula of sodium chlorate(v) is NaClO 3 Sodium chlorate(v) may be prepared by passing chlorine into hot aqueous sodium hydroxide. Balance the equation for this reaction below.... Cl +... NaOH... NaCl + NaClO 3 + 3H O (Total 1 marks) Q3. There are several types of crystal structure and bonding shown by elements and compounds. (a) Name the type of bonding in the element sodium. Page 3 of

4 Use your knowledge of structure and bonding to draw a diagram that shows how the particles are arranged in a crystal of sodium. You should identify the particles and show a minimum of six particles in a twodimensional diagram. (b) Sodium reacts with chlorine to form sodium chloride. Name the type of bonding in sodium chloride. Explain why the melting point of sodium chloride is high. (Extra space)... (c) The table below shows the melting points of some sodium halides. NaCl NaBr NaI Melting point /K Suggest why the melting point of sodium iodide is lower than the melting point of sodium bromide (Total 7 marks) Page 4 of

5 Q4. Fluorine forms many compounds that contain covalent bonds. (a) State the meaning of the term covalent bond. Write an equation to show the formation of one molecule of ClF 3 from chlorine and fluorine molecules. (b) Draw the shape of a dichlorodifluoromethane molecule (CCl F ) and the shape of a chlorine trifluoride molecule (ClF 3 ). Include any lone pairs of electrons that influence the shape. Shape of CCl F Shape of ClF 3 (c) Suggest the strongest type of intermolecular force between CCl F molecules.... (d) BF 3 is a covalent molecule that reacts with an F ion to form a BF 4 ion. Name the type of bond formed when a molecule of BF 3 reacts with an F ion. Explain how this bond is formed. Type of bond... Explanation... State the bond angle in the BF 4 ion Page 5 of

6 (e) An ultrasound imaging agent has the formula C 4 F 10 It can be made by the reaction of butane and fluorine as shown in the following equation. C 4 H F C 4 F HF Calculate the percentage atom economy for the formation of C 4 F 10 in this reaction. Give your answer to three significant figures (Total 11 marks) Q5. The following table gives the melting points of some elements in Period 3. Element Na Al Si P S Melting point / K (a) State the type of structure shown by a crystal of silicon. Explain why the melting point of silicon is very high (b) State the type of structure shown by crystals of sulfur and phosphorus. Explain why the melting point of sulfur is higher than the melting point of phosphorus Page 6 of

7 (c) Draw a diagram to show how the particles are arranged in aluminium and explain why aluminium is malleable. (You should show a minimum of six aluminium particles arranged in two dimensions.) (d) Explain why the melting point of aluminium is higher than the melting point of sodium (Total 1 marks) Q6. Trends in physical properties occur across all Periods in the Periodic Table. This question is about trends in the Period elements from lithium to nitrogen. (a) Identify, from the Period elements lithium to nitrogen, the element that has the largest atomic radius.... (b) State the general trend in first ionisation energies for the Period elements lithium to nitrogen. Page 7 of

8 Identify the element that deviates from this general trend, from lithium to nitrogen, and explain your answer. Element... Explanation... (Extra space)... (c) Identify the Period element that has the following successive ionisation energies. First Second Third Fourth Fifth Sixth Ionisation energy / kj mol (d) Draw a cross on the diagram to show the melting point of nitrogen. Page 8 of

9 (e) Explain, in terms of structure and bonding, why the melting point of carbon is high (Extra space) (Total 10 marks) Q7. Fluorine forms compounds with many other elements. (a) Fluorine reacts with bromine to form liquid bromine trifluoride (BrF 3 ). State the type of bond between Br and F in BrF 3 and state how this bond is formed. Type of bond... How bond is formed (b) Two molecules of BrF 3 react to form ions as shown by the following equation. BrF 3 BrF + + BrF 4 Draw the shape of BrF 3 and predict its bond angle. Include any lone pairs of electrons that influence the shape. Shape of BrF 3 Bond angle... Page 9 of

10 Draw the shape of BrF 4 and predict its bond angle. Include any lone pairs of electrons that influence the shape. Shape of BrF 4 Bond angle... (c) BrF 4 ions are also formed when potassium fluoride dissolves in liquid BrF 3 to form KBrF 4 Explain, in terms of bonding, why KBrF 4 has a high melting point (Extra space) (d) Fluorine reacts with hydrogen to form hydrogen fluoride (HF). State the strongest type of intermolecular force between hydrogen fluoride molecules. Draw a diagram to show how two molecules of hydrogen fluoride are attracted to each other by the type of intermolecular force that you stated in part (d). Include all partial charges and all lone pairs of electrons in your diagram. Page 10 of

11 (e) The boiling points of fluorine and hydrogen fluoride are 188 C and 19.5 C respectively. Explain, in terms of bonding, why the boiling point of fluorine is very low (Extra space) (Total 15 marks) Q8. The following table shows the electronegativity values of the elements from lithium to fluorine. Li Be B C N O F Electronegativity (a) State the meaning of the term electronegativity. (Extra space)... Suggest why the electronegativity of the elements increases from lithium to fluorine. (Extra space)... Page 11 of

12 (b) State the type of bonding in lithium fluoride. Explain why a lot of energy is needed to melt a sample of solid lithium fluoride. Bonding... Explanation (Extra space) (c) Deduce why the bonding in nitrogen oxide is covalent rather than ionic (Extra space) (d) Oxygen forms several different compounds with fluorine. Suggest the type of crystal shown by OF Write an equation to show how OF reacts with steam to form oxygen and hydrogen fluoride. Page 1 of

13 (iii) One of these compounds of oxygen and fluorine has a relative molecular mass of 70.0 and contains 54.3% by mass of fluorine. Calculate the empirical formula and the molecular formula of this compound. Show your working. Empirical formula... Molecular formula... (4) (Total 14 marks) Q9. (a) Graphene is a new material made from carbon atoms. It is the thinnest and strongest material known. Graphene has a very high melting point and is an excellent conductor of electricity. Part of the structure of graphene is illustrated in the diagram. Deduce the type of crystal structure shown by graphene. Page 13 of

14 Suggest why graphene is an excellent conductor of electricity. (iii) Explain, in terms of its structure and bonding, why graphene has a high melting point. (b) Titanium is also a strong material that has a high melting point. It has a structure similar to that of magnesium. State the type of crystal structure shown by titanium. Explain, in terms of its structure and bonding, why titanium has a high melting point. (c) Titanium can be hammered into objects with different shapes that have similar strengths. Suggest why titanium can be hammered into different shapes. Suggest why these objects with different shapes have similar strengths. Page 14 of

15 (d) Magnesium oxide (MgO) has a melting point of 315 K. Predict the type of crystal structure in magnesium oxide and suggest why its melting point is high. Type of crystal structure... Explanation (Total 13 marks) Q10. (a) Ammonia gas readily condenses to form a liquid when cooled. Name the strongest attractive force between two ammonia molecules. Draw a diagram to show how two ammonia molecules interact with each other in the liquid phase. Include all partial charges and all lone pairs of electrons in your diagram. (b) Ammonia reacts with boron trichloride to form a molecule with the following structure. State how the bond between ammonia and boron trichloride is formed Page 15 of

16 (c) The following table shows the electronegativity values of some elements. H Li B C O F Electronegativity Give the meaning of the term electronegativity. Suggest the formula of an ionic compound that is formed by the chemical combination of two different elements from the table. (iii) Suggest the formula of the compound that has the least polar bond and is formed by chemical combination of two of the elements from the table. (Total 9 marks) Page 16 of

17 Q11. In 009 a new material called graphane was discovered. The diagram shows part of a model of the structure of graphane. Each carbon atom is bonded to three other carbon atoms and to one hydrogen atom. (a) Deduce the type of crystal structure shown by graphane.... (b) State how two carbon atoms form a carbon carbon bond in graphane (c) Suggest why graphane does not conduct electricity (d) Deduce the empirical formula of graphane.... (Total 4 marks) Q1. (a) Nickel is a metal with a high melting point. State the block in the Periodic Table that contains nickel. Page 17 of

18 Explain, in terms of its structure and bonding, why nickel has a high melting point. (iii) Draw a labelled diagram to show the arrangement of particles in a crystal of nickel. In your answer, include at least six particles of each type. (iv) Explain why nickel is ductile (can be stretched into wires). (b) Nickel forms the compound nickel(ii) chloride (NiCl ). Give the full electron configuration of the Ni + ion. Balance the following equation to show how anhydrous nickel(ii) chloride can be obtained from the hydrated salt using SOCl Identify one substance that could react with both gaseous products....nicl.6h O(s) +... SOCl (g)...nicl (s) +...SO (g) +...HCl(g) Substance... (Total 9 marks) Page 18 of

19 Q13. Silicon dioxide (SiO ) has a crystal structure similar to diamond. (a) Give the name of the type of crystal structure shown by silicon dioxide.... (b) Suggest why silicon dioxide does not conduct electricity when molten (c) Silicon dioxide reacts with hydrofluoric acid (HF) to produce hexafluorosilicic acid (H SiF 6 ) and one other substance. Write an equation for this reaction.... (Total 3 marks) Q14. Which compound has the highest boiling point? A C H 4 B C H 6 C CH 3 NH D CH 3 F (Total 1 mark) Q15. Which of these substances has permanent dipole-dipole attractions between molecules? A CCl 4 B C F 4 C (CH 3 ) CO D CO (Total 1 mark) Page 19 of

20 Q16. Which of these atoms has the highest electronegativity? A B C D Na Mg Cl Ar (Total 1 mark) Q17. Which of these substances does not show hydrogen bonding? A HF B NH 3 C CH 3 COOH D CHF 3 (Total 1 mark) Q18. What is the formula of calcium nitrate(v)? A CaNO 3 B Ca(NO 3 ) C Ca NO D Ca(NO ) (Total 1 mark) Q19. Which substance exists as a macromolecule? A Cu B SiO C P 4 O 10 D MgO (Total 1 mark) Page 0 of

21 Q0. Which molecule has the largest dipole? A ClF 3 B BF 3 C SF 6 D CF 4 (Total 1 mark) Q1. The table shows some data about the elements bromine and magnesium. Element Melting point / K Boiling point / K Bromine Magnesium In terms of structure and bonding explain why the boiling point of bromine is different from that of magnesium. Suggest why magnesium is a liquid over a much greater temperature range compared to bromine (Total 5 marks) Page 1 of

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