By using Born-Haber cycle to calculate the crystal lattice energy of NaCl, discuss the heats, involved in all the changes. 

Born - Haber cycle is used to determine

Discuss Born- Haber cycle with reference to sodium chloride.

Construct a Born-Haber cycle and use it to calculate the first electron affinity of chlorine. DeltaH_(atom(CI))= +122 kJ mol^(-1) " " DeltaH_(atom(Mg))=+148 kJ mol^(-1) DeltaH_("1st ionisation energy" (Mg))=+738 KJ mol^(-1) " " DeltaH_(2nd " ionisation cnergy"(MgCI_(2))= +1451 kJ mol^(-1) DeltaH _("lattice energy "(MgCI_(2))= -2526 kJ mol^(-1) " " DeltaH_(2nd " formation "(MgCI_(2)) =-641 kJ mol^(-1)

Change in enthalpy and change in internal energy are state functions. The value of DeltaH, DeltaU can be determined by using Kirchoff's equation. Calculate the heat of formation of methane, given that heat of formation of water = -286kJ mol^(-1) , heat of combustion of methane = -890kJ mol^(-1) heat of combustion of carbon = -393.5 kJ mol^(-1)

When electron jumps from higher orbit to lower orbit, then energy is radiated in the form of electro magnetic radiation and these radiations are used to record the emission spectrum Energy of electron may be calculated as E= (2pi^2 m_e Z^2 e^4)/(n^2 h^2) where m_e = rest mass of electron DeltaE = (E_(n_2)- E_(n_1)) = 13.6xxZ^2 xx [1/(n_1^2) - 1/(n_2^2)] eV per atom This equation was also used by Rydberg to calculate the wave number of a particular line in the spectrum. bar(upsilon) = 1/(lambda) = R_H Z^2 [1/(n_1^2) -1/n_2^2] m^(-1) Where , R_H = 1.1 xx 10^7 m^(-1) (Rydberg constant) For Lyman, Balmer, Paschen, Brackett and Pfund series the value of n_1 = 1,2,3,4,5 respectively and n_2 = oo for series limit, If an electron jumps from higher orbit n to ground state than number of spectral line will be ""^nC_2 . Ritz modified the Rydberg equation by replacing the rest mass of electron with reduced mass (mu) . 1/(mu) = 1/(m_N) + 1/(m_e) , Here m_N mass of nucleus , m_e = mass of electron. The emission spectrum of He^+ involves transition of electron from n_1 to n_2 such that n_2 + n_1 = 8 and n_2 - n_1 = 4 . What will be the total number of lines in the spectrum ?

Which of the following is not involved in Born-Haber cycle?

Identify the type of energy change (ionization energy, energy of atomization, etc) show by each of these steps in the Born Haber cycle for potassium chloride. State with a reason whether the step is exothermic or endothermic. a ) 1//2 CI_(2)(g) rarr CI(g) " " b) CI(g) rarr CI^(-)(g) " " c) K(s) rarr K (g) d) K(g) rarr K^(+) (g) + e^(-) " " e) K (s) +1//2 CI_(2) (g) rarr KCI (s) " " f) KCI (s) rarr K^(+) (g) + CI^(-) (g)