QUESTION 2 Ammonium nitrate is an important fertiliser made by the acid-base reaction between ammonia and nitric acid. 2.1 Write an equation for the production of ammonium nitrate from ammonia and nitric acid. The ammonia for this reaction is produced by the Haber process and the nitric acid is produced by oxidation of ammonia. The Haber process involves a reaction between nitrogen and hydrogen at a temperature of 450 °C and a pressure of 20 000 kPa. At a higher reaction temperature, the rate of production of ammonia would be greater N2(g) + 3H2(g) < == >2NH3 ΔH = –92 kJ mol–1 The Boltzmann distribution curve shows the distribution of energies in a mixture of nitrogen and hydrogen at 450 °C.   Right-click on the button to open the data booklet in a new tab.      2.2 Sketch a second line onto the axes above to show the distribution of energies in the same mixture of gases at a higher temperature. 2.3 With reference to the two curves, explain why the rate of production of ammonia would be greater at a higher temperature. 2.4 Add a suitable label to the horizontal axis above and use it to explain why a catalyst is used in the Haber process. 2.5 Explain why a higher temperature is not used despite the fact that it would increase the rate of production of ammonia. 2.6 The first stage in the production of nitric acid involves the reaction of ammonia with oxygen to form nitrogen monoxide, NO, and water. Suggest an equation for this reaction and use oxidation numbers to show that it is a redox reaction. 2.7 Draw a dot-and-cross diagram of the ammonium ion. Show the outer electrons only. Use the following key for your electrons. • electrons from nitrogen. x electrons from hydrogen reaction. 2.8 State the shape of an ammonium ion and give the H–N–H bond angle. shape …. bond angle ….. 2.9 State and explain the problems that arise from the overuse of ammonium nitrate fertiliser when the excess is washed into rivers.    

1.28 Compound X, C4H8O2, has an unbranched carbon chain. An aqueous solution of X has an approximate pH of 3.   Compound Y, C3H8O, is a secondary alcohol. X and Y are reacted together in the presence of a little concentrated sulfuric acid to form Z as the major organic product.   What is the structural formula of Z?   A (CH3)2CHCO2CH2CH2CH3 B CH3(CH2)2CO2CH(CH3)2 C CH3(CH2)2CO2(CH2)2CH3 D (CH3)2CHCO2CH(CH3)2

1.33 What are the ionic half-equations for the electrode reactions during the electrolysis of concentrated aqueous sodium chloride?   

  QUESTION 6   The graph shows how the temperature of a substance changes as it is cooled over a period of 30 minutes. The substance is a gas at the start.   Right-click on the button to open the data booklet in a new tab.        Each letter on the graph may be used once, more than once or not at all. State when:   6.1 the particles in the substance have the most kinetic energy? 6.2 the particles in the substance are furthest apart? 6.3 the substance exists as both a gas and a liquid? 6.4 The moment that all the substance is solid? 6.5 Use the graph to estimate the freezing point of the substance. 6.6 Name the change of state directly from a solid to a gas.   When smoke is viewed through a microscope, the smoke particles in the air appear to jump around.   6.7 What term describes this movement of the smoke particles? 6.8 Explain why the smoke particles move in this way.    

1.32 Calcium carbonate reacts with dilute hydrochloric acid. The equation for the reaction is shown. CaCO3 + 2HCl — > CaCl 2 + H2O + CO2 1.00 g of calcium carbonate is added to 50.0 cm3 of 0.0500 mol / dm3 hydrochloric acid. Which volume of carbon dioxide is made in this reaction?

1.24 The diagram shows a cup of hot tea.   Right-click on the button to open the data booklet in a new tab.        Which row describes the water particles in the air above the cup compared with the water particles in the cup?   Moving faster Closer together A Yes No B Yes Yes C No No D No Yes

1.35 Carbonic acid is a weak acid formed when carbon dioxide dissolves in water. What is the pH of the solution?

1.31 Which statement describes the structure of copper?  

1.17 Which properties of the element titanium, Ti, can be predicted from its position in the Periodic Table?     can be used as a catalyst   conducts electricity when solid has low density   forms coloured compounds   A Yes Yes No Yes B Yes Yes Yes No C Yes No Yes Yes D No Yes Yes Yes

1.30 A method used to investigate the rate of reaction of calcium carbonate with dilute hydrochloric acid under different conditions is shown.   ● Place 50 cm3 of dilute hydrochloric acid in a conical flask. ● Add a known volume of water to the conical flask. ● Heat the conical flask to the required temperature. ● Add 1.0 g of calcium carbonate to the conical flask. ● Measure the time taken for the reaction to finish.   Which volume of water and which temperature gives the shortest time taken for the reaction to finish?     volume of water added / cm3 temperature / °C A 10 30 B 10 50 C 40 30 D 40 50