Answer all questions and look at the marks for each question and show all working out.

In the behaviour of catalysts, defects often play a vital role. (a) With the aid of diagrams, explain in general terms why surface defects can have such a big impact on catalytic activity. (7 marks) (b) Sketch the structure of a Frenkel defect in CuO, justifying why you have drawn it the way that you have. (4 marks) (c) As a \% of the total number of atoms, calculate the number of Frenkel defects that would be present in the CuO at 575K, considering that H =3.121019J. Note that Ni=4N for this structure. (4 marks)