Estimatiom of bond energy

  • #1
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10

Homework Statement


Estimate the average S-F bond energy in SF6 The standard heat of formation values of SF6(g) , S(g) and F)(g) are: -1100, 275 and 80 kj / mol respectively.





Homework Equations


∆H=∆Hf (products) -∆Hf(Reactants)

S(g) +6F)(g) ------>SF6(g)

The Attempt at a Solution



I found the ∆H formation of the reaction which I got -1455 kJ/ mol and taking this as my bond energy. But My answer doesn't match so can you tell me what am I doing wrong [/B]
 

Answers and Replies

  • #2
Borek
Mentor
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I found the ∆H formation of the reaction which I got -1455 kJ/ mol and taking this as my bond energy.
That would be true for a molecule with SF formula.
 
  • #3
mjc123
Science Advisor
Homework Helper
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First, your calculation of ∆H is wrong; you have only taken account of one F. Second, how many S-F bonds are formed in the reaction? How do you work out the average energy per bond? Third, bond energy is the energy released by forming a bond, or the energy consumed by breaking a bond - it is a positive quantity. How is it related to ∆H?
 
  • #4
First, your calculation of ∆H is wrong;
Yes, -1455kJ/mol is not the right answer.

Harambe, you need to answer questions like: how many bonds thee are in the reagents, how many bonds there are in the products... also the request energy is only for 1 bond.
 

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