The first ionization enthalpy (IE) of the third period elements 'Na, M g', and 'S i' are respectively 496,737 and '786(kJ mol^(-1)) .' Predict whether the first 'IE' value for 'Al' will be more close to 575 or '760 kJ' mol '^(-1)'. Justify your answer.

The enthalpy of formation of NaCl(s) is -411.2 kJ mol^(-1). The enthalpy of sublimation of Na(s), its ionization enthalpy in the gaseous state, the bond energy of chlorine, its electron gain enthalpy are 108.4, 495.6, 242 and -348.6 kJ mol^(-1) respectively. The energy required to break one mole of solid sodium chloride into its ions in the gaseous state is (in kJ)

In the Arrhenius equation for a first order reaction, the value of A and E_{a} are 4xx10^13 sec^-1 and 98.6 kj mol^-1 respectively. At what temperature will its half life be 10 minutes?

One mole of magnesium in the vapour state absorbed 1200 kJ 'm o l^(-1)' of energy. If the first and second ionization energies of 'Mg' are 750 and '1450 kJ mol^(-1)' respectively, the final composition of the mixture is