What is the correct procedure for calculating energy change to form KI(s)?

Click For Summary
SUMMARY

The correct procedure for calculating the energy change to form 1.05 moles of KI(s) involves several steps, including the sublimation of iodine (I2), the vaporization of potassium (K), and the ionization of both elements. The relevant energy values are: I2(s) to I2(g) at 62.44 kJ/mol, K(s) to K(g) at 180.4 kJ/mol, and the lattice energy for KI at -649 kJ/mol. The user incorrectly attempted to sum the energy values and multiply by 1.05 moles without properly accounting for stoichiometry, particularly for iodine.

PREREQUISITES
  • Understanding of thermodynamic principles, specifically Hess's Law
  • Familiarity with enthalpy changes and energy calculations
  • Knowledge of ionic compounds and lattice energy concepts
  • Basic stoichiometry for chemical reactions
NEXT STEPS
  • Review Hess's Law and its application in energy calculations
  • Study the concept of lattice energy and its significance in ionic compounds
  • Learn about the Born-Haber cycle for calculating formation energies
  • Practice stoichiometric calculations involving gaseous and solid states
USEFUL FOR

Chemistry students, educators, and professionals involved in thermodynamics and energy calculations in chemical reactions.

tangents
Messages
21
Reaction score
0
Hello all I just need to know if the procedure I'm taking is right.

I need to find energy change of 1.05 Mol of KI(s) given that:

I2(s) → I2(g) : 62.44 KJ/mol
K(s) → K(g) : 180.4 KJ/mol
1/2 I2(g) → I(g) : 138.05 KJ/mol
K+(g) + e− → K(g) : −419 KJ/mol
I−(g) → I(g) + e− : 295.16 KJ/mol
Lattice energy for KI = −649 KJ/mol

I tried adding all the values and then multiplying by 1.05 mol but that doesn't seem to work so then what I did was multiply 1.05 by the lattice energy and then add up all the values but I still am not getting the correct answer. There is a diagram in my text and I followed every step yet am I doing something wrong?
 
Physics news on Phys.org
tangents said:
still am not getting the correct answer.
Check the iodine stoichiometry.
 

Similar threads

Replies
2
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
6
Views
4K
  • · Replies 19 ·
Replies
19
Views
4K
Replies
3
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
Replies
6
Views
3K
Replies
4
Views
3K