Consider the gas-phase transfer of an electron from a sodium atom to a chlorine atom:

Question

Na(g)+Cl(g)-->Na^(+)(g)+Cl^(-)(g)

I was able to write the reaction that relates to an ionization energy and that relates to an electron affinity.

I broke it up into:
Na(g)--> Na^(+)+e^(-)
Cl(g)+ e^(-)--> Cl^(-)(g)
Which was correct, but I'm having trouble with how I'm supposed to use these equations to calculate the enthalpy of the above reaction. I have to use Hess's Law and then some given data but I don't know which.

How should I approach this problem? Explanation would be great, thanks.

Answer 1

You don't tell us what the problem is. Post the problem as is.

Answer 2

Part B: Use the result from part A, data in this chapter (Chapter 7:Periodic Properties of the Elements), and Hess's law to calculate the enthalpy of the above reaction.

Part A is:
Na(g)--> Na^(+)+e^(-)
Cl(g)+ e^(-)--> Cl^(-)(g)

Answer 3

You want to use the ionization potential (in joules) + electron affinity (in joules). Add them together to arrive at dHrxn. Usually the electron affinity is given for the Cl2 molecule; you will need to take 1/2 that. Usually that's a negative number while the IP is a positive dH.