View Full Version : Chem help please?
glycogen
Dec3-04, 09:11 PM
Given: Cl2 = 58 kcal/mole ------> 2cl
1. 58 kcal/mole is the bond dissociation energy T F
2. 58 kcal/mole is an entropy term T F
3. this reactin is endothermic T F
I dont understand get it! Any help woud be appreciated.
Astronuc
Dec3-04, 09:50 PM
Did you mean to write Cl_2+58 kcal/mole \rightarrow 2 Cl?
If so, then think about what it means. What is happening when Cl_2 \rightarrow 2 Cl?
What are you doing with the energy?
Can it be the 'entropy' term?
so-crates
Dec3-04, 10:46 PM
Thats one notation. Most textbooks nowadays would say
Cl_2 \longrightarrow 2 Cl \ \ \ \ \Delta H^0 = +58 \ \ kcal/mol
to avoid confusion about the "energy" change in the system. (At constant pressure, enthalpy = heat added or lost)
A positive enthalphy change corresponds with heat being absorbed by the system. A negative enthalpy change corresponds to heat being released by the system.
glycogen
Dec4-04, 04:42 PM
Thanks for the explanations :). The formula makes sense now!
vBulletin® v3.8.7, Copyright ©2000-2012, vBulletin Solutions, Inc.