Enthalpies of solution and hydration — Paper 1 · A Level Chemistry 9701

8 Use of the Data Booklet is relevant to this question. The enthalpy change of formation, ∆Hf, of hydrated calcium ions is the enthalpy change of the following reaction. Ca(s) + aq – 2e– → Ca2+(aq) The following enthalpy changes are not quoted in the Data Booklet. Ca(s) → Ca(g) ∆Ha = 177 kJ mol–1 Ca2+(g) + aq → Ca2+(aq) ∆Hhyd = –1565 kJ mol–1 What is the enthalpy change of formation of hydrated calcium ions? A –1388 kJ mol–1 B –798 kJ mol–1 C –238 kJ mol–1 D +352 kJ mol–1

1 marks

Answer: D

This question in 9701/12 Oct/Nov 2010

5 In the table below, • ‘+’ means that this type of standard enthalpy change can only have positive values, • ‘–’ means that this type of standard enthalpy change can only have negative values, • ‘+ / –’ means that either positive or negative values are possible. Which row is correct? atomisation formation solution A + + + / – B + + / – + / – C – + / – – D – – +

1 marks

Answer: B

This question in 9701/11 Oct/Nov 2012

5 In the table below, • ‘+’ means that this type of standard enthalpy change can only have positive values, • ‘–’ means that this type of standard enthalpy change can only have negative values, • ‘+ / –’ means that either positive or negative values are possible. Which row is correct? atomisation formation solution A + + + / – B + + / – + / – C – + / – – D – – +

1 marks

Answer: B

This question in 9701/12 Oct/Nov 2012

33 For which enthalpy changes is the value of ∆H always negative? 1 combustion 2 hydration 3 solution

1 marks

Answer: B

This question in 9701/11 Oct/Nov 2016

33 For which enthalpy changes is the value of ∆H always negative? 1 combustion 2 hydration 3 solution

1 marks

Answer: B

This question in 9701/13 Oct/Nov 2016

33 For which enthalpy changes is the value of ∆H always negative? 1 combustion 2 hydration 3 solution

1 marks

Answer: B

This question in 9701/13 May/June 2019

32 Which statements are correct? 1 enthalpy of combustion of H2 = enthalpy of formation of H2O 2 enthalpy of formation of H2 = –(enthalpy of atomisation of H2) 3 enthalpy of solution of HCl = enthalpy of hydration of H+ + enthalpy of hydration of Cl –

1 marks

Answer: D

This question in 9701/11 Oct/Nov 2020

8 Which pair of enthalpy changes will always share the same sign (i.e. both are always exothermic or both are always endothermic)? A enthalpy change of atomisation and enthalpy change of neutralisation B enthalpy change of atomisation and enthalpy change of solution C enthalpy change of combustion and enthalpy change of hydration D enthalpy change of solution and enthalpy change of hydration

1 marks

Answer: C

This question in 9701/12 Oct/Nov 2020

32 Which statements are correct? 1 enthalpy of combustion of H2 = enthalpy of formation of H2O 2 enthalpy of formation of H2 = –(enthalpy of atomisation of H2) 3 enthalpy of solution of HCl = enthalpy of hydration of H+ + enthalpy of hydration of Cl –

1 marks

Answer: D

This question in 9701/13 Oct/Nov 2020

32 The diagram shows an incomplete energy profile diagram for a reaction. products enthalpy reactants progress of reaction Which reactions could this diagram refer to? 1 CaCO3(s)  CaO(s) + CO2(g) 2 H2(g)  2H(g) 3 Cl –(aq)  Cl –(g) + aq

1 marks

Answer: A

This question in 9701/11 May/June 2021

7 Using the information in the table, what is the enthalpy change, q, for the reaction described? Cs+(g) + Br –(g)  CsBr(s) ∆H = q kJ mol–1 standard value enthalpy change / kJ mol–1  H o CsBr(s) +25.9 sol  H o Cs+(g) –276 hyd  H o Br –(g) –335 hyd A –636.9 B –585.1 C +585.1 D +636.9

1 marks

Answer: A

This question in 9701/13 May/June 2021