AS Chemistry Question paper Paper 1 June 2017

1 *jun177404101* IB/M/Jun17/E7 7404/1 For Examiner s Use Question Mark 1 2 3 4 5 6 7 8 Section B TOTAL Friday 26 May 2017 Morning Time allowed: 1 hour 30 minutes Materials For this Paper you must have: the Periodic Table/Data Sheet, provided as an insert (enclosed) a ruler with millimetre measurements a calculator, which you are expected to use where appropriate. Instructions Use black ink or black ball-point pen. Fill in the boxes at the top of this page. Answer all questions.

2 You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. All working must be shown. Do all rough work in this book. Cross through any work you do not want to be marked. Information The marks for questions are shown in brackets. The maximum mark for this Paper is 80. Advice You are advised to spend about 65 minutes on Section A and 25 minutes on Section B. Please write clearly in block capitals. Centre number Candidate number Surname Forename(s) Candidate signature AS Chemistry Paper 1: Inorganic and Physical Chemistry 2 *02* IB/M/Jun17/7404/1 Do not write outside the box Section A Answer all questions in this section.

3 0 1 This Question is about atomic structure. 0 1 . 1 Write the full electron configuration for each of the following species. [2 marks] Cl Fe2+ 0 1 . 2 Write an equation, including state symbols, to represent the process that occurs when the third ionisation energy of manganese is measured. [1 mark] 0 1 . 3 State which of the elements magnesium and aluminium has the lower first ionisation energy. Explain your answer. [3 marks] 3 *03* Turn over IB/M/Jun17/7404/1 Do not write outside the box 9 0 1.

4 4 A sample of nickel was analysed in a time of flight (TOF) mass spectrometer. The sample was ionised by electron impact ionisation. The spectrum produced showed three peaks with abundances as set out in Table 1. Table 1 m/z Abundance / % 58 60 61 Give the symbol, including mass number, of the ion that would reach the detector first in the sample. Calculate the relative atomic mass of the nickel in the sample. Give your answer to one decimal place. [3 marks] Symbol of ion Relative atomic mass 4 *04* IB/M/Jun17/7404/1 Do not write outside the box 0 2 This Question is about energetics.

5 0 2 . 1 Write an equation, including state symbols, for the reaction with an enthalpy change equal to the enthalpy of formation for iron(III) oxide. [1 mark] 0 2 . 2 Table 2 contains some standard enthalpy of formation data. Table 2 CO(g) Fe2O3(s) fH o / kJ mol 1 111 822 Fe2O3(s) + 3CO(g) 2Fe(s) + 3CO2(g) H = 19 kJ mol 1 Use these data and the equation for the reaction of iron(III) oxide with carbon monoxide to calculate a value for the standard enthalpy of formation for carbon dioxide.

6 Show your working. [3 marks] fH o kJ mol 1 5 *05* Turn over IB/M/Jun17/7404/1 Do not write outside the box 8 0 2 . 3 Some enthalpy data are given in Table 3. Table 3 Process H / kJ mol 1 N2(g) + 3H2(g) 2NH3(g) 92 N2(g) 2N(g) +944 H2(g) 2H(g) +436 Use the data from Table 3 to calculate the bond enthalpy for N H in ammonia. [3 marks] N H bond enthalpy kJ mol 1 0 2 . 4 Give one reason why the bond enthalpy that you calculated in Question is different from the mean bond enthalpy quoted in a data book (388 kJ mol 1).

7 [1 mark] 6 *06* IB/M/Jun17/7404/1 Do not write outside the box 0 3 A student planned and carried out an experiment to determine the enthalpy of reaction when magnesium metal displaces zinc from aqueous zinc sulfate. Mg(s) + Zn2+(aq) Mg2+(aq) + Zn(s) The student used this method: A measuring cylinder was used to transfer 50 cm3 of a mol dm 3 aqueous solution of zinc sulfate into a glass beaker. A thermometer was placed in the beaker. g of magnesium metal powder were added to the beaker.

8 The mixture was stirred and the maximum temperature recorded. The student recorded a starting temperature of oC and a maximum temperature of oC. 0 3 . 1 Show by calculation which reactant was in excess. Use the data to calculate the experimental value for enthalpy of reaction in kJ mol 1(Assume that the specific heat capacity of the solution is J K 1g 1and the density of the solution is g cm 3). [6 marks] Reactant in excess Enthalpy of reaction kJ mol 1 7 *07* Turn over IB/M/Jun17/7404/1 Do not write outside the box 0 3.

9 2 Another student used the same method and obtained a value for the enthalpy of reaction of 142 kJ mol 1 A data book value for the enthalpy of reaction is 310 kJ mol 1 Suggest the most likely reason for the large difference between the student s experimental value and the data book value. [1 mark] Question 3 continues on the next page 8 *08* IB/M/Jun17/7404/1 Do not write outside the box 13 0 3 . 3 Suggest how the students method, and the analysis of the results, could be improved in order to determine a more accurate value for the enthalpy of reaction.

10 Justify your suggestions. Do not refer to the precision of the measuring equipment. Do not change the amounts or the concentration of the chemicals. [6 marks] 9 *09* Turn over IB/M/Jun17/7404/1 Do not write outside the box 4 0 4 When substances P and Q react together to form substance R an equilibrium is established according to the equation P(g) + Q(g) 2R(g)