The overall energy involved in the formation of CsCl from Cs(s) and Cl2 (g)is - 443 kj/mol. Given the following information:
•heat of sublimation for Cs is +76 kj/mol,
•bond dissociation energy for ½ Cl2is +121 kj/mol,
•E(11) for Cs is +376 kj/mol, and
•E(a) for Cl2is 349 kj/mol.
what is the magnitude of the lattice energy for CsCl?
in kj/mol
attempted
i guess the formula we ahve to use is
U= k ( z1 x z2)/ d
but i don't knw which is which
so plz can someone
need help badly
someone can plz solveit for me
thnks
ybe
U=(-443-76-121-376+349)
=-667
Well, it seems like you need some help with the calculation. Let me try to assist you!
First, let's identify the relevant values for the calculation:
- The heat of sublimation for Cs is +76 kJ/mol.
- The bond dissociation energy for ½ Cl2 is +121 kJ/mol.
- E(11) for Cs is +376 kJ/mol.
- E(a) for Cl2 is 349 kJ/mol.
The lattice energy (U) for CsCl can be calculated using the formula:
U = (k * (z1 * z2)) / d
Now, let's assign the values:
- z1 is the charge of the Cs ion, which is +1.
- z2 is the charge of the Cl ion, which is -1.
- d is the distance between the ions, which we can approximate as the sum of their ionic radii.
However, we need another piece of information to calculate the lattice energy: the Madelung constant (k). Unfortunately, you haven't provided it in the given information.
Considering all this, I'm afraid I can't provide you with an exact numerical answer for the magnitude of the lattice energy for CsCl. But hey, at least we had some fun trying to solve it together, right? Keep up the good work!
To determine the magnitude of the lattice energy for CsCl, we can use the Born-Haber cycle. The lattice energy (U) can be calculated using the following equation:
U = (H(sub) + H(ion) - H(diss) - H(atom) - H(formation)) / n
where:
- H(sub) is the heat of sublimation for Cs
- H(ion) is the ionization energy for Cs (E(11))
- H(diss) is the bond dissociation energy for Cl2
- H(atom) is the electron affinity for Cl2 (E(a))
- H(formation) is the enthalpy of formation for CsCl
- n is the stoichiometric coefficient of CsCl, which is 1 in this case
Given the given information:
- H(sub) = +76 kJ/mol
- H(ion) = +376 kJ/mol
- H(diss) = +121 kJ/mol
- H(atom) = +349 kJ/mol
- H(formation) = -443 kJ/mol
- n = 1
We can substitute these values into the equation to solve for U:
U = (76 + 376 + 121 + 349 - (-443)) / 1
= (76 + 376 + 121 + 349 + 443) / 1
= 1365 kJ/mol
Therefore, the magnitude of the lattice energy for CsCl is 1365 kJ/mol.
That 376 sounds high for the ionization potential. Also, did you make a typo on the Ea for Cl. I think that should be -349 (or at least the number should be negative). I don't know if the number is correct or not.
Assuming E(11) is the ionization potential for Cs(g) ==> Cs^+ +e
then
Sublimation + ionization + 1/2 dissociation + electron affinity + Ecrystallization = heat formation.
If your numbers are right, then 76+376+121-349+Ecrystallization = -443. Solve for E crystal.
Most P. Chem texts I've seen define U as crystal lattice energy = - E crystal.
Solve for E crystallization. E crystal should be a negative number