. a) Draw a band diagram for magnesium (12 Mg). Label the valence and conduction bands. See notes for answer 25% b) Draw a band diagram for silicon. Label the valence and conduction bands. See notes for answer c) Draw a band diagram for silicon doped with gallium. Label the valence and conduction bands. See notes for answer d) Explain briefly what you can do to increase the maximum current for the semiconductor type youve drawn in part c. Increase the dopant to substrate ratio 25% 3. The following process is used for the industrial production of sodium phosphate: H3PO4(g) + 3 NaOH(s) Na3PO4(s) + 3 H2O(l) a) Calculate the standard state enthalpy for the reaction 232 kJ b) Calculate the standard state entropy for the reaction 13.9 J/K c) Calculate the standard state free energy at 85 C 237 kJ d) Is the reaction spontaneous at 85 C? Explain your choice briefly. YES; G is positive 25% 4. A 3.0M solution of sodium chloride has a density of 1.14 g/ml. Determine its normal freezing point 12C Data and equations : ln (P2 P1 ) = Hvap R ( 1 T1 1 T2 ) R = 8.314 J/Kmol T(K) = T(C) + 273 R = 0.08206 Latm/Kmol A = 6.02 x 1023 Tb = Kb m Kb (H2O) = 0.52 C/m Tf = Kf m Kf (H2O) = 1.86 C/m standard thermodynamic data at 25C H f (kJ/mol) S (J/Kmol) G f (kJ/mol) H3PO4(g) 1271.7 150.8 1123.6 NaOH(s) 425.6 64.5 379.5 Na3PO4(s) 1923 148.3 1867.4 H2O(g) 241.83 188.84 288.72