ACSI Paper 2 Prelim

1 YEAR 6 PRELIMINARY EXAMINATION 2023 INTERNATIONAL BACCALAUREATE DIPLOMA PROGRAMME CHEMISTRY HIGHER LEVEL PAPER 2 Wednesday 13 th September 2023 2 hours 15 minutes INSTRUCTIONS TO CANDIDATES  Do not open this examination paper until instructed to do so.  Write your candidate session number in the box above.  A calculator is required for this paper.  A copy of the Chemistry Data Booklet is required for this paper.  Write your answers in the boxes provided.  If you use additional sheets of paper for your answer, attach them to the booklet. Indicate the question number clearly on these sheets.  All drawings must be in ink. For examiner’s use Qn 1 /6 Qn 2 /22 Qn 3 /8 Qn 4 /10 Qn 5 /13 Qn 6 /9 Qn 7 /15 Qn 8 /7 Wrong s.f. /units Total /90 ________________________________________________________________________ This question paper consists of 31 printed pages including this cover page. Name Candidate Number

2 Answer all questions. Write your answers in the boxes provided. 1. Carbon consists of 4 allotropes in the form of diamond, graphite, fullerene and graphene. (a) State and explain the difference in electrical conductivity of diamond and graphite. [2] ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ..................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... (b) Explain why the carbon-carbon bonds in graphite are stronger than the carbon- carbon bonds found in diamond. [2] ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... (This question continues on the following page)

3 (Question 1 continued) (c) State the type of hybridization of the carbon atoms in diamond and graphite. [2] Diamond: …………………………………………………………………………………………………... Graphite: …………………………………………………………………………………………………… 2. The energy cycle shown can be used to calculate the enthalpy change of formation of KCl (s). Each arrow indicates a transformation, W, X, and Y. Each transformation consists of one or more steps. (a) (i) Calculate the value of the following transformations using section 8 of the data booklet and the following information. Enthalpy change of atomisation of K (s) +89 kJ mol─1 Enthalpy change of atomisation of Cl2 (g) +121 kJ mol─1 Enthalpy change of solution of KCl (s) 17 kJ mol─1 Enthalpy change of hydration of Cl─(g) 365 kJ mol─1 Enthalpy change of hydration of K+(g) 340 kJ mol─1 [4] (This question continues on the following page)

4 (Question 2 continued) Transformation W: K (s) + 1 2Cl2 (g)  K+ (g) + Cl─ (g) ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... Transformation Y: K+ (g) + Cl─ (g)  KCl (aq) ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... (ii) Using your answer to (a)(i) and the given data to calculate the enthalpy change of formation of KCl (s). If you did not get answers to (a)(i), use +200 kJ mol─1 and 650 kJ mol─1 for W and Y respectively, but these are not the correct answers. [2] ….................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... (This question continues on the following page)

5 (Question 2 continued) (a) (iii) State and explain the sign for the entropy change for the formation of KCl (s). [1] ...................................................................................................................................................... ...................................................................................................................................................... (iv) Deduce, giving reasons, whether altering the temperature would change the spontaneity for the formation of KCl (s). [2] ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... (b) Explain why the enthalpy change of hydration of K+ is less exothermic than that of Ca2+. [1] ...................................................................................................................................................... ...................................................................................................................................................... (This question continues on the following page)

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