a) Two radioactive nuclei decay by successive first order processes as follows: x y z The half-life for the first step is 22.5 days and 33.0 days for the second step. (i) Calculate ki and k. Suppose Y is an isotope that is required for medical applications calculate the time that Y will be most abundant. [10 marks) b) The rate constant for the enzyme-catalysed decomposition of hydrogen peroxide, H2O2, increases by a factor of 3.8 when the temperature is increased from 298 K to 348 K. Determine the activation energy. [10 marks] c) The rates of the forward and reverse reaction were found to be 5.1 x 10 dm' mol's! and 1.9 x 10's respectively. Calculate the equilibrium constant for the reaction. [5 marks)