Chemistry: Heat of Sublimation and Hydrogem Bonds Problem

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SUMMARY

The discussion focuses on calculating the change in enthalpy for the sublimation of water (H2O) from solid to gas, with a determined value of 46.7 kJ/mol. Participants also address the contribution of hydrogen bonding to intermolecular forces in ice, referencing a ΔH value of -21 kJ/mol from Exercise 24. The conversation emphasizes the need to clarify the ΔH values associated with sublimation and desublimation processes.

PREREQUISITES
  • Understanding of thermodynamics, specifically enthalpy changes.
  • Knowledge of phase transitions, including sublimation and desublimation.
  • Familiarity with intermolecular forces, particularly hydrogen bonding.
  • Ability to interpret and apply thermodynamic equations.
NEXT STEPS
  • Research the concept of enthalpy of sublimation and its calculation methods.
  • Study the role of hydrogen bonds in determining the properties of ice and water.
  • Learn about the relationship between heats of fusion, vaporization, and sublimation.
  • Explore the implications of ΔH values in chemical reactions and phase changes.
USEFUL FOR

Chemistry students, educators, and researchers interested in thermodynamics, phase transitions, and the properties of water and ice.

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Homework Statement


Using the heats of fusion and vaporization for water, calculate the change in enthalpy for the sublimation of water:

H2O(s) --> H2O(g

Using the delta H value given in Exercise 24 and the number of hydrogen bonds formed to each water molecule, estimate what portion of the intermolecular forces in ice can be accounted for by hydrogen bonding.

Homework Equations

The Attempt at a Solution


I have already figured out the first portion of the problem, finding the change in enthalpy of sublimation ( I got 46.7 kJ/mol ), but I'm really not sure as to how to attack the portion of IMF and hydrogen bonding. Any help is greatly appreciated.
 
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And what was the ΔH value given in the exercise 24? ΔH of what?
 
Borek said:
And what was the ΔH value given in the exercise 24? ΔH of what?
I believe it's -21 kJ/mol
 
ΔH of what?
 
Borek said:
ΔH of what?
of the reaction H20 (g) + HOH (g) -> H2O --- HOH (in ice)
 
What is ΔH of the desublimation?
 

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