QUESTION 6   When 2.00 mol of PCl5(g) are decomposed at 450 K and 1.00 × 105 Pa the resulting equilibrium mixture contains 0.800 mol of Cl2 (g).   PCl5 (g) < == > PCl3 (g) + Cl2 (g)   6.1 Calculate the partial pressure of phosphorus (V) chloride, pPCl5, in this equilibrium mixture. [2] 6.2 Write the expression for the equilibrium constant, Kp, for the decomposition of PCl5(g). [1]     [3]

1.24 Which organic compound would not give either a yellow precipitate when treated with alkaline aqueous iodine or an orange precipitate when treated with 2,4-dinitrophenylhydrazine reagent?

1.21 Fluorine and iodine are Group 17 elements. Their melting points are different due to differing strengths of the van der Waals’ forces between molecules. Which row is correct?      Right-click on the button to open the data booklet in a new tab.  

1.9 Dicarbon monoxide, C2O, is found in dust clouds in space. The structure of this molecule is C=C=O. The molecule contains no unpaired electrons. How many lone pairs of electrons are present in a molecule of C2O?

QUESTION 3 This question is about an ester with molecular formula C4H8O2   The infra-red spectra of the ester and of another compound, X, are shown. X decolourises bromine water and is not an ester or an acid.   Right-click on the button to open the data booklet in a new tab.     Right-click on the button to open the data booklet in a new tab.       3.1 Draw the displayed diagrams of a possible isomer with the formula C4H8O2 that is an ester. [1] 3.2 Give the reagents and conditions needed to produce an ester. [2] 3.3 Explain the differences between these two spectra, with particular reference to the peaks with wavenumbers above 1500 cm–1. [3]     [6]

1.15 A piece of rock has a mass of 2.00 g. It contains calcium carbonate, but no other basic substances. It neutralises exactly 36.0 cm3 of 0.500 mol.dm–3 hydrochloric acid. What is the percentage of calcium carbonate in the 2.00 g piece of rock?

1.18 The equation for the complete combustion of propan-1-ol is shown.   Right-click on the button to open the data booklet in a new tab.        What is the standard enthalpy change of combustion of propan-1-ol, in kJ/mol?

1.1 What will make it more likely that a gas will approach ideal behaviour?

1.29 Three elements, X, Y and Z, have electronic configurations as shown. X 2,6 Y 2,8,1 Z 2,8,7   Which formulae represent compounds that conduct electricity in the liquid state?   1 YZ 2 Y2X 3 Z2X

1.7 Methanol may be prepared by the reaction between carbon monoxide and hydrogen. CO(g) + 2H2(g) → CH3OH(g) The relevant average bond energies are given below. E (C ≡ O) 1077 kJ/ mol E (C – O) 360 kJ/ mol E (C – H) 410 kJ/ mol E (H – H) 436 kJ/ mol E (O – H) 460 kJ/ mol What is the enthalpy change of this reaction?