Question

Using standard thermodynamic tables and the following data, compute the crystal enthalpy of AgBr(c) using the Born-Haber cycle. The CRC Handbook lists the value as 904 kJ/mol. Compute the % difference between this value and your result.

**Data:**

Ag(g) Ag^{+}(g) +
e^{-}
7.576 eV

Br(g) + e^{-}
Br^{-}(g)
324.5 kJ/mol

Answer #1

Lattice energy= Heat of formation- Heat of atomization- Dissociation energy- Ionization energies- Electron Affinities

Heat of formation of AgBr = −99.5 KJ/mol

Heat of atomization of Ag = 285 KJ/mol

BOnd dissociation energy of Br2 = 192 KJ/mol / 2 = 96 KJ/mol

Electron affinity = - 324.5 KJ/mol (energy is released)

Ionisation energy = 7.576 eV = 7.576*1.602*10^-19*6*10^23 = 728.205 KJ/mol

1 eV = 1.602*10^-19 J ( for 1 mole we are calculating)

Substituting all values

Lattice energy = - 884.205 KJ/mol

% difference = [904 - 884.205] *100 / 884.205 = 2.46%

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the standard thermodynamic data in the tables linked above,
calculate G for this reaction at 298.15K if the pressure of each
gas is 17.64 mm Hg.
ANSWER:_____ kJ/mol

1. NH4Cl(aq)<->NH3(g) + HCl(aq)
Using the standard thermodynamic data in the tables linked
above, calculate the equilibrium constant for this reaction at
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2. HCl(g) +
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Using the standard thermodynamic data in the tables linked above,
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calculate the bond dissociation energy of F2.
Na(g) → Na+(g) + e-(g) ΔrH = IE1 =
500 kJ mol-1
Na(s) → Na(g) ΔsubH = 107 kJ
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F-(g) → F(g) + e-(g) ΔrH = EA1 = 329
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Na(s) + 1/2 F2(g) → NaF(s) ΔfH =
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N2(g) +
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Using the standard thermodynamic data in the tables linked above,
calculate Grxn for this reaction at 298.15K if the
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4HCl(g) +
O2(g)------>2H2O(g)
+ 2Cl2(g)
Using the standard thermodynamic data in the tables linked above,
calculate G for this reaction at 298.15K if the pressure of each
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Using the thermochemical data and an estimated value of -2235.2
kJ/mol for the lattice energy for potassium oxide, calculate the
value for the second electron affinity of oxygen
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Quantity
Numerical Value
(kJ/mol)
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89
Ionization energy of K
418.8
Enthalpy of formation of solid K2O
-363
Enthalpy of formation of O(g) from O2(g)
249.1
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Mass of salt, g = 5.00
Mass of calorimeter, g = 5.10
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Initial Temperature, °C = 25.35
Final Temperature. °C = 17.19
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below.
delta Hfo (kJ/mol)
o (J/mol K
C(graphite)
0.0
5.740
C(diamond)
1.895
2.377
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