13618.06R 14 Ethane (CH3CH3) and methylamine (CH3NH2) have similar relative molecular masses. (a) (i) Draw a dot and cross diagram to show the bonding in a molecule of methylamine. [1] (ii) State the value for the H C H bond angles in a methylamine molecule. [1] (iii) Suggest and explain the shape around the nitrogen atom in a methylamine molecule. [3] 13618.06R [Turn over (b) (i) Define electronegativity. [1] (ii) Show the polarity of the N H bond below, using partial charges. N H [1] (iii) Predict which of the compounds, ethane or methylamine, has the higher boiling point. Explain the difference in boiling points between these two compounds. [3] 13618.06R (c) Methylamine is a weak base and a solution of methylamine reacts with strong acids to form the methylammonium ion (CH3NH3 +). (i) Write an equation for the reaction of methylamine with sulfuric acid to form methylammonium sulfate. [2] (ii) Explain, with reference to the type of bond formed, how a methylamine molecule forms a methylammonium ion. [2] (iii) Draw a diagram to show two hydrogen bonds which can form between one methylamine molecule and two water molecules. Show all lone pairs. [2] 13618.06R BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over