1.12 Elements D and E are both in Period 3. Element D has the smallest atomic radius in Period 3. There are only two elements in Period 3 which have a lower melting point than element E. Elements D and E react together to form compound L. Which compound could be L  A  MgCl2 B MgS C Na2S D PCl 3

1.11 Why is the ionic radius of a chloride ion larger than the ionic radius of a sodium ion?

1.13 X and Y are both Group 2 metals. X and Y both form hydroxide compounds, but X(OH)2 is more soluble in water than Y(OH)2. If a piece of metal Y is put into cold water a very slow reaction occurs, and only few small hydrogen bubbles can be seen. What could the identities of X and Y be?  

1.26 How many of the following compounds produce a carboxylic acid on heating under reflux with an excess of hot acidified K2Cr2O7?   CH3CH2CHO CH3COCH3 CH3CH2CH2OH CH3CH(OH)CH3

1.6 Aluminium carbide, Al4C3, reacts readily with aqueous sodium hydroxide. The two products of the reaction are NaAlO2 and a hydrocarbon. Water molecules are also involved as reactants. What is the formula of the hydrocarbon?   A CH4 B C2H6 C C3H8 D C6H12

1.2   Which mass of urea, CO(NH2)2, contains the same mass of nitrogen as 101.1 g of potassium nitrate?

1.4 Which isolated gaseous atom has a total of five electrons occupying spherically shaped orbitals?

1.3 The relative atomic mass of copper is 63.5. Which chart is the correct mass spectrum that would lead to this value?   Right-click on the button to open the data booklet in a new tab.    

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