# Calculate Energy Change for CO + Cl2 Reactions - Help!

• claudzterz9
In summary, the energy change that occurs when carbon monoxide and chlorine combine to make phosgene can be estimated by using the average bond energies for the reactants and products. By subtracting the two, the estimated energy change is -100 kJ/mol.
claudzterz9
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.

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

## 1. What is the formula for calculating energy change for CO + Cl2 reactions?

The formula for calculating energy change for CO + Cl2 reactions is ΔH = ΣH(products) - ΣH(reactants), where ΔH is the change in enthalpy and ΣH is the sum of the enthalpies of the products and reactants.

## 2. How do you determine the enthalpy of a substance?

The enthalpy of a substance can be determined by measuring the amount of heat released or absorbed during a reaction. It can also be calculated using Hess's Law, which states that the enthalpy change of a reaction is the sum of the enthalpy changes of its individual steps.

## 3. Can the energy change for CO + Cl2 reactions be negative?

Yes, the energy change for CO + Cl2 reactions can be negative. A negative value indicates that the reaction is exothermic, meaning that heat is released during the reaction.

## 4. What factors can affect the energy change for CO + Cl2 reactions?

The energy change for CO + Cl2 reactions can be affected by factors such as temperature, pressure, and the concentrations of the reactants and products. Changes in these factors can alter the equilibrium of the reaction, leading to a different energy change.

## 5. How is the energy change for CO + Cl2 reactions related to the overall stability of the products?

The energy change for CO + Cl2 reactions is directly related to the overall stability of the products. A more negative energy change indicates a more stable product, as the reaction releases more energy in the form of heat. Conversely, a less negative or positive energy change indicates a less stable product.

• Biology and Chemistry Homework Help
Replies
2
Views
2K
• Biology and Chemistry Homework Help
Replies
5
Views
2K
• Biology and Chemistry Homework Help
Replies
7
Views
2K
• Biology and Chemistry Homework Help
Replies
4
Views
2K
• Biology and Chemistry Homework Help
Replies
3
Views
2K
• Biology and Chemistry Homework Help
Replies
5
Views
6K
• Biology and Chemistry Homework Help
Replies
1
Views
1K
• Biology and Chemistry Homework Help
Replies
8
Views
3K
• General Math
Replies
3
Views
2K
• Biology and Chemistry Homework Help
Replies
4
Views
4K