Official June 2024 AQA A-LEVEL CHEMISTRY 7405/1 Paper 1 Inorganic and Physical Chemistry Merged Question Paper + Mark Scheme + Insert Ace your Mocks!!! *Jun247405101* IB/M/Jun24/G4006/E9 7405/1 For Examiner’s Use Question Mark 1 2 3 4 5 6 7 8 9 TOTAL Monday 10 June 2024 Morning Time allowed: 2 hours Materials For this paper you must have: • the Periodic Table/Data Booklet, provided as an insert (enclosed) • a ruler with millimetre measurements • a scientific 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. • You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. • If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s). • 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 105. Please write clearly in block capitals. Centre number Candidate number Surname Forename(s) Candidate signature I declare this is my own work. A-level CHEMISTRY Paper 1 Inorganic and Physical Chemistry 2 *02* IB/M/Jun24/7405/1 Do not write outside the Answer all questions in the spaces provided. box 0 1 This question is about atomic structure. 0 1 . 1 In 1897 JJ Thomson discovered the electron. He suggested that atoms were positively charged spheres with electrons embedded within them. Figure 1 represents an atom using Thomson’s model. Figure 1 Suggest the identity of this atom. Give two differences between the modern model of an atom and the Thomson model of an atom. [3 marks] Identity Difference 1 Difference 2 3 *03* Turn over ► IB/M/Jun24/7405/1 Do not write outside the box 0 1 . 2 Tellurium has a relative atomic mass of 127.6 Iodine has a relative atomic mass of 126.9 Define relative atomic mass. Suggest one property of tellurium that justifies its position before iodine in the modern Periodic Table. [3 marks] Definition Justification 0 1 . 3 A sample of tellurium is analysed in a time of flight (TOF) mass spectrometer using electron impact ionisation. Give an equation, including state symbols, for this ionisation. [1 mark] Question 1 continues on the next page 4 *04* IB/M/Jun24/7405/1 Do not write outside the box 0 1 . 4 In the TOF mass spectrometer an ion of an isotope of tellurium, with mass number y, travels along a 1.25 m flight tube with a kinetic energy of 1.88 x 10–12 J The ion takes 3.00 x 10–7 s to reach the detector. KE = 1 2 mv2 KE = kinetic energy / J m = mass / kg v = speed / m s–1 Calculate the mass, in g, of 1 mole of these tellurium ions. Use your answer to suggest the mass number y of the tellurium isotope. The Avogadro constant, L = 6.022 × 1023 mol–1 [5 marks] Mass g Mass number y 5 *05* Turn over ► IB/M/Jun24/7405/1 Do not write outside the box 0 1 . 5 Tellurium has several other isotopes. Two of these isotopes are 126Te and 124Te A different sample of tellurium is analysed using a TOF mass spectrometer. Which statement about kinetic energy (KE) is correct? [1 mark] Tick () one box. The KE of 126Te+ is greater than the KE of 124Te+ The KE of 126Te+ is the same as the KE of 124Te+ The KE of 126Te+ is less than the KE of 124Te+ Turn over for the next question 13 6 *06* IB/M/Jun24/7405/1 Do not write outside the There are no questions printed on this page box DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED 7 *07* Turn over ► IB/M/Jun24/7405/1 Do not write outside the box 0 2 This question is about an experiment to determine the solubility of strontium hydroxide in water at 20 °C Strontium hydroxide is slightly soluble in water. Strontium hydroxide solution reacts in a similar way to calcium hydroxide solution. • Some solid strontium hydroxide is added to approximately 1 dm3 of distilled water in a stoppered flask. • The mixture is kept at 20 °C. Every day, the mixture is checked. If no solid is present in the flask, more solid strontium hydroxide is added. • On the day when no more solid needs to be added, the flask is opened and the mixture is filtered into another flask and stoppered. • A 25.0 cm3 sample of the filtrate is transferred to a conical flask with a pipette and a few drops of indicator added. • This sample is titrated with 0.100 mol dm–3 hydrochloric acid. • The titration is repeated several times with further samples of the filtrate. The results are shown in Table 1 on page 8. 0 2 . 1 Suggest why the solution is kept until no more solid needs to be added. [1 mark] 0 2 . 2 Suggest why it is important to remove the undissolved strontium hydroxide before the titration. [1 mark] 0 2 . 3 After the filtration, the solution is stored in a stoppered flask. Suggest a reason for stoppering the flask. [1 mark] Question 2 continues on the next page 8 *08* IB/M/Jun24/7405/1 Do not write outside the box 0 2 . 4 The diagrams in Figure 2 show the part of a pipette with the graduation line. Which diagram identifies the pipette that is correctly filled? [1 mark] Tick () one box. Figure 2 A B C 0 2 . 5 Solubility can be quoted as ‘g of solute per 100 cm3 of solution’. Table 1 shows the results of the titrations between strontium hydroxide and hydrochloric acid. These can be used to determine the solubility of strontium hydroxide. Table 1 Titration Rough 1 2 3 Final burette reading / cm3 34.40 38.00 41.05 37.00 Initial burette reading / cm3 0.00 5.55 8.05 4.60 Titre / cm3 34.40 32.45 33.00 32.40 Give the equation for the reaction between strontium hydroxide and hydrochloric acid. Use the results in Table 1 to calculate the mean titre. Use the mean titre to calculate the solubility of strontium hydroxide, in g per 100 cm3 of solution, at 20 °C [6 marks]