3 Trends in Lattice Enthalpy

 

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Oxford Textbook Pages : 263, 267 - 268

CGP Revision Guide Pages : 57

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Show Specification Ref : 3.1.8.1

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Question 1 / 5

AQA Jun 2016 Paper 2 Q6 do not write outside the box the halogens are the elements in group a the electronegativities of the halogens are shown in table table halogen fluorine chlorine bromine iodine electronegativity explain the trend in electronegativities shown by the halogens marks b the halogens can all behave as oxidising agents in reactions b i explain in terms of electron transfer the meaning of the term oxidising agent mark b ii an equation for the reaction that takes place when chlorine gas is bubbled through aqueous potassium bromide is shown cl g kbr aq br aq kcl aq explain with reference to the oxidation states why this is a redox reaction mark wmp jun chem do not write outside the box c solid sodium halides react with concentrated sulfuric acid c i a sample of solid sodium iodide is reacted with concentrated sulfuric acid a black solid forms and hydrogen sulfide gas is produced write a half equation for the reaction of sulfuric acid to form hydrogen sulfide mark c ii write a half equation for the formation of the black solid mark c iii use your answers to parts c i and c ii to write an overall equation for the reaction of sodium iodide with concentrated sulfuric acid mark c iv give the role of sulfuric acid in its reaction with sodium iodide tick one box mark acid oxidising agent reducing agent electrophile c v write an equation for the reaction of concentrated sulfuric acid with solid sodium fluoride mark c vi suggest one reason why the reaction of sodium fluoride with concentrated sulfuric acid is different from the reaction with sodium iodide mark turn over wmp jun chem do not write outside the box d chlorine reacts with water to form an equilibrium mixture containing hydrochloric acid and chloric i acid d i write an equation for the formation of this equilibrium mixture mark d ii household bleach contains sodium chlorate i and sodium chloride state and explain with reference to your equation in part d i why it is dangerous to acidify an aqueous mixture of sodium chlorate i and sodium chloride marks wmp jun chem
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Question 2 / 5

AQA Jan 2010 Paper 5 Q4 the table below gives some values of standard enthalpy changes use these values to answer the questions areas outside the box will not be scanned for marking name of enthalpy change h kj mol enthalpy of atomisation of chlorine electron affinity of chlorine enthalpy of atomisation of silver first ionisation enthalpy of silver enthalpy of formation of silver chloride a calculate the bond enthalpy of a cl cl bond mark b explain why the bond enthalpy of a cl cl bond is greater than that of a br br bond marks c suggest why the electron affinity of chlorine is an exothermic change mark wmp jan chem d the diagram below is an incomplete born haber cycle for the formation of silver chloride the diagram is not to scale areas outside the box will not be scanned for marking ag g cl g ag s cl g agcl s d i complete the diagram by writing the appropriate chemical symbols with state symbols on each of the three blank lines marks d ii calculate a value for the enthalpy of lattice dissociation for silver chloride marks question continues on the next page turn over wmp jan chem areas outside the box will not be scanned for marking e the enthalpy of lattice dissociation for silver chloride can also be calculated theoretically assuming a perfect ionic model e i explain the meaning of the term perfect ionic model mark e ii state whether you would expect the value of the theoretical enthalpy of lattice dissociation for silver chloride to be greater than equal to or less than that for silver bromide explain your answer theoretical lattice enthalpy for silver chloride explanation marks extra space e iii suggest why your answer to part d ii is greater than the theoretical value for the enthalpy of lattice dissociation for silver chloride marks wmp jan chem there are no questions printed on this page do not write on this page answer in the spaces provided turn over wmp jan chem
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Question 3 / 5

AQA Jun 2012 Paper 5 Q3 do not write outside the box some thermodynamic data for fluorine and chlorine are shown in the table in the table x represents the halogen f or cl electronegativity electron affinity kj mol enthalpy of atomisation kj mol enthalpy of hydration of x g kj mol fluorine chlorine a explain the meaning of the term electron affinity marks b explain why the electronegativity of fluorine is greater than the electronegativity of chlorine marks extra space c explain why the hydration enthalpy of the fluoride ion is more negative than the hydration enthalpy of the chloride ion marks wmp jun chem do not write outside the box d the enthalpy of solution for silver fluoride in water is kj mol the hydration enthalpy for silver ions is kj mol d i use these data and data from the table to calculate a value for the lattice enthalpy of dissociation of silver fluoride marks d ii suggest why the entropy change for dissolving silver fluoride in water has a positive value mark d iii explain why the dissolving of silver fluoride in water is always a spontaneous process marks turn over wmp jun chem
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Question 4 / 5

AQA Jun 2013 Paper 5 Q1 section a answer all questions in the spaces provided do not write outside the box a define the term lattice enthalpy of dissociation marks b lattice enthalpy can be calculated theoretically using a perfect ionic model explain the meaning of the term perfect ionic model mark extra space c suggest two properties of ions that influence the value of a lattice enthalpy calculated using a perfect ionic model property property marks wmp jun chem do not write outside the box d use the data in the table to calculate a value for the lattice enthalpy of dissociation for silver chloride enthalpy change value kj mol enthalpy of atomisation for silver first ionisation energy for silver enthalpy of atomisation for chlorine electron affinity for chlorine enthalpy of formation for silver chloride marks e predict whether the magnitude of the lattice enthalpy of dissociation that you have calculated in part d will be less than equal to or greater than the value that is obtained from a perfect ionic model explain your answer prediction compared with ionic model explanation marks turn over wmp jun chem
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Question 5 / 5

AQA Jun 2014 Paper 5 Q1 section a answer all questions in the spaces provided do not write outside the box a write an equation for the process that has an enthalpy change equal to the electron affinity of chlorine mark b in terms of electrostatic forces suggest why the electron affinity of fluorine has a negative value marks c i complete the born haber cycle for silver fluoride by adding the missing species on the dotted lines marks ag g ag g ag g f g ag g ag s agf s wmp jun chem do not write outside the box c ii use the cycle in question c i and the data in table to calculate a value in kj mol for the bond enthalpy of the fluorine fluorine bond table enthalpy change enthalpy of atomisation for silver first ionisation energy for silver electron affinity for fluorine experimental enthalpy of lattice dissociation for silver fluoride enthalpy of formation for silver fluoride marks value kj mol question continues on the next page turn over wmp jun chem do not write outside the box d a theoretical value for enthalpy of lattice dissociation can be calculated using a perfect ionic model the theoretical enthalpy of lattice dissociation for silver fluoride is kj mol d i explain why the theoretical enthalpy of lattice dissociation for silver fluoride is different from the experimental value that can be calculated using a born haber cycle marks extra space d ii the theoretical enthalpy of lattice dissociation for silver chloride is kj mol explain why this value is less than the value for silver fluoride marks extra space wmp jun chem turn over for the next question do not write on this page answer in the spaces provided turn over wmp jun chem
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