We’re being asked to calculate the lattice energy of NaCl2 needed for the reaction to be exothermic.
Recall that lattice energy is the energy required to combine two gaseous ions into a solid ionic compound:
Mx+(g) + Ny–(g) → MyNx(s)
To calculate for lattice energy, we need to do the Born-Haber cycle for NaCl2.
We start with the corresponding formation equation for NaCl2:
Na(s) + Cl2(g) → NaCl2(s), ΔH˚f
Construct a Born-Haber cycle for the formation of the hypothetical compound NaCl2, where the sodium ion has a 2+ charge (the 2nd ionization energy for sodium is given in Table 7.2 in the textbook).
How large would the lattice energy need to be for the formation of NaCl2 to be exothermic?
Frequently Asked Questions
What scientific concept do you need to know in order to solve this problem?
Our tutors have indicated that to solve this problem you will need to apply the Born Haber Cycle concept. You can view video lessons to learn Born Haber Cycle. Or if you need more Born Haber Cycle practice, you can also practice Born Haber Cycle practice problems.
What professor is this problem relevant for?
Based on our data, we think this problem is relevant for Professor Bartels' class at University of Manitoba.