Paper 1 – Inorganic and Physical Chemistry Predicted Paper 2022

01 ropanoic acid dissociates slightly in aqueous solution. 01.1 Write an expression for the acid dissociation constant Ka for propanoic acid. P [1 mark] …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… 01.2 The Ka value of propanoic acid is 1.35×10-5 moldm-3. A buffer solution is prepared containing 2.15×10-2 mol of propanoic acid and 1.50×10-2 mol of sodium propanoate in 1.00 dm3 solution. I. Calculate the pH of the buffer solution 25°C. [3 marks] …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… II. A small amount of aqueous NH3(aq) is added to the buffer solution. Explain how the buffer solution would respond to the added NH3(aq). [2 marks] …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… III. The student adds 0.25 g of Mg to 1.00 dm3 of the buffer solution. Calculate the pH of the new buffer solution. (Mr = 24.3 g/mol) [3 marks] …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… Primrose Kitten – YouTube Tutorials for GCSE and A-Level 02 A sample of X was analysed by mass spectrometry. The following results were obtained for the atoms of X in the sample. Relative isotopic mass Relative abundance 16 99.82 17 0.04 18 0.14 02.1 Calculate the relative atomic mass of element X. Give your answer to two decimal places. [2 marks] ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… 02.2 Identify the element X. [1 mark] ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… 02.3 The most abundant isotope of the X in that sample was 16X. I. Write the formulae of two different ions which might be formed in the mass spectrometer. [2 marks] ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… Primrose Kitten – YouTube Tutorials for GCSE and A-Level II. Which part of the mass spectrometer separates ions from different mass? [1 mark] ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… III. State how vapourised atoms of X are converted into X+ ions in a mass spectrometer. [2 marks] ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… Primrose Kitten – YouTube Tutorials for GCSE and A-Level 03 The model Valence Shell Electron Pair Repulsion Theory (VSEPR) can be used to deduce the shapes and bond angles in simple molecules. 03.1 Complete the following table using simple fluoride containing compounds. One example has been included. [3 marks] Number of bond pairs Number of lone pairs Shape of molecules Formula of a molecule with this shape 2 0 Linear BeF2 3 1 5 0 4 2