Answer all questions in this section.

Total value of this section: 80

1. State the first and second laws of thermodynamics. [4 marks]
2. Give an example of a natural phenomenon for which classical mechanics has no explanation but which can be explained using quantum mechanics. [2 marks]
3. Using as an example, explain the difference between bonding and antibonding molecular orbitals. [5 marks]
4. Do you expect to be a stable molecule? Explain briefly. [4 marks]
5. What is the ground state electronic configuration of a scandium atom? [4 marks]
6. How much heat is released or absorbed when 50g of sodium hydroxide is dissolved in water? [6 marks]
7. 1. One of the diamond industry's favorite advertising lines is that ``diamonds are forever''. A reasonable thermodynamic interpretation of this line is that the reaction

      

      is not spontaneous under normal conditions. Is this true? [2 marks]

   2. In reactions which involve only solids or liquids, we generally ignore any terms proportional to PV, such as the work. Calculate the work done when one mole of diamond is converted to one mole of graphite at 298K under a constant pressure of 1atm. Based on your calculation, would it normally be acceptable to neglect the work? The density of diamond is while the density of graphite is . [8 marks]
   3. Calculate , and for the conversion of diamond to graphite at accurately. [12 marks]
   4. Calculate for the conversion of diamond to graphite at using the approximation that and are approximately constant and equal to their values at 298K. Compare your answer to that obtained in the last part of this question. If you had not had enough data to do a detailed calculation and had been forced to use the approximate method, would the free energy change obtained have been of any value? [3 marks]
8. 1. The solubility of nitrogen in water at under a pressure of pure nitrogen of 1atm is . Calculate the free energy of formation of an aqueous nitrogen molecule. [5 marks]
   2. The solubility of nitrogen in water at is . Calculate the enthalpy of formation of an aqueous nitrogen molecule. [5 marks]
9. Suppose that an electron in a box makes a transition from the ground state to the first excited state while absorbing a photon of wavelength 250nm. What is the length of the box? [10 marks]
10. Some cells take in phosphate by reacting it with ADP to form ATP (and water). This fulfills two cellular needs simultaneously, namely phosphate uptake and ATP synthesis, but the process is not spontaneous under realistic conditions. The driving force is provided by the spontaneous flow of protons across the cell membrane. The pH outside the cell is typically lower than the pH inside by 1.5 units. Three protons flow into the cell for every phosphate transported in. If the concentration of phosphate outside the cell is and the concentration of ADP inside the cell is , what is the maximum concentration of ATP which can be reached inside the cell at 298K due to this process alone? For the reaction , at 298K. [10 marks]