Official June 2024 AQA AS CHEMISTRY 7404/1 Paper 1 Inorganic and Physical Chemistry Merged Question Paper + Mark Scheme + Insert Ace your Mocks!!! *JUN247404101* IB/M/Jun24/G4001/V7 7404/1 For Examiner’s Use Question Mark 1 2 3 4 5 6 7 8 9 Section B TOTAL Tuesday 14 May 2024 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 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 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 I declare this is my own work. AS CHEMISTRY Paper 1 Inorganic and Physical Chemistry 2 *02* IB/M/Jun24/7404/1 Do not write outside the Section A box Answer all questions in this section. 0 1 A student does a series of reactions with aqueous solutions of some potassium halides (P, Q and R) of equal concentration. Each solution contains a different halide ion (chloride, bromide or iodide). The student adds 3 drops of bromine water to 3 drops of each aqueous solution of potassium halide. The student also adds 3 drops of the bromine water to 3 drops of water. Table 1 shows the student’s observations. Table 1 Observation when 3 drops of bromine water are added Solution P Orange solution Solution Q Brown solution Solution R Orange solution Water Orange solution 0 1 . 1 Identify the halide ion present in Q. Give the ionic equation for the reaction that occurs when bromine water is added to Q. [2 marks] Halide ion in Q Ionic equation 3 *03* Turn over ► IB/M/Jun24/7404/1 Do not write outside the box 0 1 . 2 Explain, in terms of oxidising ability, why the observations from these reactions do not allow the student to identify the halide ion present in P and the halide ion present in R. [2 marks] 0 1 . 3 The student does a second experiment to determine the halide ion in each of P and R. The student adds a few drops of aqueous silver nitrate solution to 2 cm3 of each potassium halide solution. Table 2 shows the student’s observations. Table 2 Student’s Observation P Precipitate formed R Precipitate formed Describe a further chemical test that the student can complete on the precipitates formed to identify the halide ion present in P and the halide ion present in R. Describe how the observations from this test can be used to identify the halide ion present in P and the halide ion present in R. [3 marks] Turn over for the next question 7 4 *04* IB/M/Jun24/7404/1 Do not write outside the box 0 2 This question is about the elements in Group 2. 0 2 . 1 Explain why the third ionisation energy of beryllium is much higher than the second ionisation energy of beryllium. [3 marks] 0 2 . 2 Magnesium reacts slowly with cold water but rapidly with steam. Compare these reactions, in terms of the products formed. You should identify one similarity in, and one difference between, these reactions. [2 marks] Similarity Difference 0 2 . 3 The reaction of calcium with water is a redox reaction. Explain, in terms of oxidation states, why this reaction involves both oxidation and reduction. [2 marks] 7 5 *05* Turn over ► IB/M/Jun24/7404/1 Do not write outside the Turn over for the next question box DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED 6 *06* IB/M/Jun24/7404/1 Do not write outside the box 0 3 This question is about structure and bonding. 0 3 . 1 Define electronegativity. [1 mark] 0 3 . 2 Explain why the C–Cl bond is polar. [2 marks] 0 3 . 3 Although the C–Cl bond is polar, CCl4 is a non-polar molecule. Explain why. [2 marks] 7 *07* Turn over ► IB/M/Jun24/7404/1 Do not write outside the box 0 3 . 4 There are van der Waals forces between non-polar molecules. Explain what causes these forces. [3 marks] Barium reacts with oxygen to form barium oxide. Barium oxide has a high melting point and an ionic lattice structure similar to that of sodium chloride. 0 3 . 5 Draw a 3D diagram to show how the particles are arranged in a barium oxide lattice. You should draw eight particles. [2 marks] 10 8 *08* IB/M/Jun24/7404/1 Do not write outside the box 0 4 A student is provided with separate unlabelled samples of four different solutions for analysis. The four solutions are known to be ammonium nitrate, potassium sulfate, sodium carbonate and magnesium nitrate, but the student does not know which sample is which. Outline a series of test-tube reactions that the student can use to identify each of these solutions. Include: • the expected observations • ionic equations for any reactions. [6 marks] 9 *09* Turn over ► IB/M/Jun24/7404/1 Do not write outside the box 6 10 *10* IB/M/Jun24/7404/1 Do not write outside the box 0 5 SF6 and SF3 + have different shapes and different bond angles. Deduce the shape of SF6 and the shape of SF3 + State the bond angle in SF6 and the bond angle in SF3 + Justify the bond angles by referring to electron pairs. [6 marks] 6 11 *11* Turn over ► IB/M/Jun24/7404/1 Do not write outside the Turn over for the next question box DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED 12 *12* IB/M/Jun24/7404/1 Do not write outside the box 0 6 This question is about atomic structure and mass spectrometry. 0 6 . 1 Give the full electron configuration for Br [1 mark] A sample of bromine (Br2) is analysed in a mass spectrometer. The sample is ionised using electron impact ionisation. 0 6 . 2 Give an equation, including state symbols, for the process that occurs during the ionisation of bromine. [1 mark] 13 *13* Turn over ► IB/M/Jun24/7404/1 Do not write outside the box 0 6 . 3 Bromine exists as two isotopes, 79Br and 81Br, which exist in equal abundance. Figure 1 shows an incomplete mass spectrum for this sample of bromine. Figure 1 Complete the spectrum by adding a label to each axis, and adding any further peaks you would expect to see. [3 marks] 0 6 . 4 State how the detector enables the relative abundance of each ion to be determined. [1 mark] Turn over for the next question 6 14 *14* IB/M/Jun24/7404/1 Do not write outside the box 0 7 Some runners take tablets to help muscle recovery after long races. These tablets contain magnesium oxide. A student wants to find the percentage by mass of magnesium oxide in the tablets. Magnesium oxide reacts with hydrochloric acid to form magnesium chloride. MgO + 2HCl ⟶ MgCl2 + H2O In an experiment, the student adds excess hydrochloric acid to some tablets. The student then does a titration using sodium hydroxide to find how much of the excess acid is left. HCl + NaOH ⟶ NaCl + H2O The student follows this method: Step 1 Place a beaker on a balance and record the mass. Step 2 Add 6 tablets to the beaker and record the mass. Step 3 Add 25.0 cm3 of 2.00 mol dm–3 hydrochloric acid to the beaker and stir until all the magnesium oxide has reacted. Step 4 Make the mixture up to 250 cm3 with distilled water in a volumetric flask. Step 5 Transfer 25.0 cm3 of this diluted mixture to a conical flask. Step 6 Add 3 drops of a suitable indicator. Step 7 Add 0.0900 mol dm–3 sodium hydroxide solution from a burette until the indicator changes colour. Repeat Steps 5 to 7 until concordant results are obtained. Results: Mass of 6 tablets = 2.14 g Mean titre = 20.38 cm3 0 7 . 1 Each reading from the balance has an uncertainty of ±0.005 g Calculate the percentage uncertainty in using the balance in this experiment. [1 mark]