Calculate the overall energy change in kilojoules per mole for the formation of

Question

Calculate the overall energy change in kilojoules per mole for the formation of CaCL(s) from the elements. The following data are needed: (a) Eea for CL(g) = -348.6kj/mol. (b) Ei1 for Ca(g) = +589.8kj/mol. (c) Ei2 for Ca(g) = +1145kj/mol. Heat of sublimation for Ca(s) = +178.2kj/mol. Bond dissociation energy for Cl2(g) = +243kj/mol. Lattice energy for CaCL2(s) = +2258kj/mol. Lattice energy for CaCL(s) = +717kj/mol (estimated) (Use the data from the above to calculate an overall energy change for the formation of CaCL2(s) from the elements. Which is more likely to form, CaCL or CaCL2?)

Explanation / Answer

(1)Li (s) -------> Li (g) .....?H = sublimation energy = 159.4 (2)Li (g) ------> Li (+) (g) + e(-) ......?H = ionization energy = 520 (3)1/2F2 (g) --------> F (g) ...?H = dissociation energy/2 = 158/2 = 79 (4)F (g) + e(-) -------> F(-) (g) ....?H = electron affinity = -328 (5)Li(+) (g) + F(-) (g) --------> LiF (s) ....?H = lattice enegy = -1036 (lattice enrgy is always negative) adding (1) + (2) + (3) + (4) + (5) = ?Hf Li (s) + 1/2F2(g) -------> LiF (s)...?Hf = 159.4 + 520 + 79 + (-328) + (-1036) = -605.6 energy change for the formation is -605.6

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.