13618.06R 13 Elements and compounds show different types of bonding and structure. (a) Describe the bonding and structure of carbon (graphite) and oxygen and explain the difference in the melting points of the two substances. In this question you will be assessed on your written communication skills including the use of specialist scientific terms. [6] 13618.06R [Turn over (b) Carbon (graphite) reacts with oxygen and with ozone (O3). Both reactions form carbon dioxide. (i) Write an equation for the reaction of carbon (graphite) with ozone. [1] (ii) Describe a chemical test for carbon dioxide. [1] (iii) Explain why carbon dioxide is non-polar. [2] (c) Carbon dioxide reacts with potassium hydroxide to form potassium carbonate. Potassium carbonate is an ionic compound which melts at 891° C and is very soluble in water. (i) State how you could show experimentally that potassium carbonate is an ionic compound based on its physical properties. [1] (ii) Write an equation for the formation of potassium carbonate from carbon dioxide and potassium hydroxide. [1] 13618.06R (iii) Describe how you would carry out a flame test on a sample of solid potassium carbonate to show the presence of potassium ions. [3] 13618.06R BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over