Chemistry Paper 1 ..tough Questions

[diwash]

Hello every one ...Some one who is reading this thread may be angry with me saying why to open a new thread when there are so many threads for Chemistry P1. I agree with the one who thinks so ..but i opened this thread to post the Q that u have found very difficult to get answer and have not got the correct answer. So lets post here... and help each other :good:
I will start with myself..
..........................................................
what is the enthalpy change for...
Cl2(g)-------2Cl-(anion)(g) ?

( the electron affinity of chlorine Cl(g).........2Cl-(anion)(g) is -364 kj/mol)

A.-120 Kj/mol
B. -244 Kj/mol
C. -484 kj/mol
D -608kj/mol

the answer is C..but i could not get it...Can anyone help me with it....

 

[hassam]

electron affinity of an element is the energy given off when a neutral atom in the gas phase gains an extra electron to form a negatively charged ion. A fluorine atom in the gas phase, for example, gives off energy when it gains an electron to form a fluoride ion.

F(g) + e- F-(g) Ho = -328.0 kJ/mol

this is its definition....
so 1 st of all u hav to convert Cl2 into atoms....by breaking bod....that would be +ve....then u ll add this to 2*(E. AFFINITY)

 

[diwash]

thanks dude...