Calculate the Electron Affinity of F(g) in kJ/mole using Hess' Law?

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SUMMARY

The discussion focuses on calculating the electron affinity of fluorine gas (F(g)) using Hess' Law, with specific values provided for ionization energies and enthalpies. The relevant data includes the ionization energies (IE1 + IE2) of strontium (Sr(g)) at 1580 kJ, the enthalpy of sublimation (Hsub) of strontium at 144 kJ, the dissociation enthalpy (Hdiss) of fluorine (F2) at 79 kJ, the formation enthalpy (Hf) of strontium fluoride (SrF2) at -1215 kJ, and the lattice enthalpy (Hlatt) of SrF2 at -2441 kJ. The user attempted to manipulate the equations to derive the electron affinity but encountered an issue with an extra half molecule of F2 that could not be canceled out.

PREREQUISITES
  • Understanding of Hess' Law and its application in thermochemistry
  • Knowledge of enthalpy changes including sublimation, dissociation, and formation
  • Familiarity with ionization energy concepts and calculations
  • Ability to manipulate chemical equations and balance reactions
NEXT STEPS
  • Study Hess' Law applications in calculating enthalpy changes
  • Learn about the concept of electron affinity and its significance in chemistry
  • Review the process of balancing chemical equations involving multiple steps
  • Explore the relationship between lattice energy and ionic compound stability
USEFUL FOR

Chemistry students, particularly those studying thermodynamics and reaction energetics, as well as educators seeking to clarify Hess' Law applications in calculating electron affinities.

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Homework Statement


Calculate the Electron Affinity of F(g) in kJ/mole using Hess' Law.
IE1 + IE2 of Sr(g) is 1580 kj
Hsub of Sr(s) is 144 kJ
Hdiss of F2 is 79 kJ
Hf of SrF2 (s) is -1215 kJ
Hlatt of SrF2 (s) is -2441 kJ

Homework Equations



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The Attempt at a Solution


1. Sr(g)+Sr+(g) -> Sr2+(g) + Sr+(g) + 2e-
2. Sr (s) -> Sr(g)
3. F2(g) -> 2F(g)
4. Sr(s) + F2(g) -> SrF2
5. Sr2+(g) + F-(g) -> SrF2 (s)

I tried to:

flip 5
1/2 * flip 3
flip 1
flip 2
copy 4

but when I did that, I ended up with an extra 1/2 F2 that I couldn't cancel out. I'm not sure what to do.
 
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In 5. there is a 2 missing before F-
 

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