Question 11-12-13 Please help me A common way of initiating certain chemical rea

Question

Question 11-12-13
Please help me

A common way of initiating certain chemical reactions with light involves the generation of free halogen atoms in solution. If { for the reaction Cl2(g) 2Cl(g) is 242.8 kJ/mol, what isthe longest wavelength in (nm) of light that will produce free chlorine atoms in solution? 1) a) 246.3 b) 465.2 c) 349.3 d) 698.6 e) 492.6 Determine the longest wavelength o light required to remove an electron from a sample of potassium metal, if the binding energy for an electron in K is 1760 kJ/mol. a) 147 nnm b) 68 nm c) 113 nm d) 885 nm e) 387 nmm Calculate the enthalpy of formation (AH) in (ki/mol) for the following reaction: (sublimation) for Na 13) Na(s) + ½ Br2(g)--> NaBr(s) 107 k/moll +))-1 (-9h2) c )) H(firstion zation) for Nat+496k/mo 15" -97 k/mol AH (dissociation) for Br2 (g) b) -367 c) +222 d) -428 e) +785 v- AH (electron affinity) for Br-325 kJ/mol K'laH(lattice energy) for NaBr -742k/mol] aBo and enery

Explanation / Answer

11. dH = 242.8 kJ/mol

            = 242.8 x 1000/6.023 x 10^23

            = 4.03 x 10^-19 J

wavelength of light = planks's constant x speed of light/energy

                              = 6.626 x 10^-34 x 3 x 10^8/4.03 x 10^-19

                              = 492.6 nm

Answer,

e) 492.6 nm

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12. Binding energy = 1760 kJ/mol

                               = 1760 x 1000/6.023 x 10^23

                               = 2.92 x 10^-18 J

longest wavelength = planks's constant x speed of light/energy

                                = 6.626 x 10^-34 x 3 x 10^8/2.92 x 10^-18

                                = 68 nm

Answer,

b) 68 nm

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13. dHf for NaBr = dHsubl[Na] + dH[IE Na] + dHdiss[Br2] + dH(IE Br] + dHlattice

feeding values from the table

dHf = 107 + 496 + 97 - 325 - 742

       = -367 kJ/mol

Answer,

b) -367

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