Calculate Energy Change for CO + Cl2 Reactions - Help!

  • Thread starter Thread starter claudzterz9
  • Start date Start date
AI Thread Summary
The discussion focuses on estimating the energy change for the reaction of carbon monoxide and chlorine to form phosgene (Cl2CO). Participants suggest using bond energy values to calculate the energy change, noting the transition from a triple bond in CO to a double bond in phosgene, along with the changes in chlorine bonds. One contributor estimates the reaction energy to be approximately -100 kJ/mol by comparing the average bond energies of the reactants and products. The calculation involves subtracting the total bond energies of the products from those of the reactants. Overall, the method emphasizes the importance of bond energies in determining reaction enthalpy.
claudzterz9
Messages
1
Reaction score
0
I am not sure how to find this... estimate the energy change that occurs when carbon monoxide and chlorine combine to make phosgene...

CO(g) + Cl2(g) ---> Cl2CO(g)

i have an idea of what to do,except i think its not the right way.
 
Physics news on Phys.org
They do not give enthalpies of formation or Bond dissociation energies?
 
claudzterz9 said:
I am not sure how to find this... estimate the energy change that occurs when carbon monoxide and chlorine combine to make phosgene...

CO(g) + Cl2(g) ---> Cl2CO(g)

i have an idea of what to do,except i think its not the right way.

Maybe you want to have a look to the thread " Enthalpy change and activation energy".
 
claudzterz9, you can do that by reacting CO and Cl2 in a calorimeter, by measuring temperatures before and after reaction.
 
take the bond energy values from your data booklet...
 
claudzterz9 said:
I am not sure how to find this... estimate the energy change that occurs when carbon monoxide and chlorine combine to make phosgene...

CO(g) + Cl2(g) ---> Cl2CO(g)

i have an idea of what to do,except i think its not the right way.

If your problem is to estimate it from given bond energies, as Kushal wrote, then in the reaction

CO(g) + Cl2(g) ---> COCl2(g)

1. You go from a triple bond in CO to a double bond between C and O in COCl2; so you have to compute this difference of energy.
2. You loose a Cl-Cl bond and you gain 2 C-Cl bonds

So, calling E1 the energy of the triple bond between C and O, E2 the energy of double bond between C and O in phosgene, E3 the bond energy Cl-Cl and E4 the bond energy C-Cl, you have, as estimated reaction energy:

E2 - E1 + 2E4 - E3 ~ 128 kJ/mol with the data I've found (but remember there is quite variation on these kind of data).

Edit. The reaction enthalpy is the same but with sign changed.
 
Last edited:
lightarrow said:
If your problem is to estimate it from given bond energies, as Kushal wrote, then in the reaction

CO(g) + Cl2(g) ---> COCl2(g)

1. You go from a triple bond in CO to a double bond between C and O in COCl2; so you have to compute this difference of energy.
2. You loose a Cl-Cl bond and you gain 2 C-Cl bonds

So, calling E1 the energy of the triple bond between C and O, E2 the energy of double bond between C and O in phosgene, E3 the bond energy Cl-Cl and E4 the bond energy C-Cl, you have, as estimated reaction energy:

E2 - E1 + 2E4 - E3 ~ 128 kJ/mol with the data I've found (but remember there is quite variation on these kind of data).

Edit. The reaction enthalpy is the same but with sign changed.

the answer u r looking for is -100 KJ/mol...

how i got it is by lookin at the avg bond energies for the reactants and the sum for that is 1310 and then i lloked for the the sum of the avg bond energies for the product whih is 1410...

subtract the 2 and you get -100 kj/mol
 
Back
Top