Ions in solids and solutions.

CI 4.5 and revision of 5.1

Ions in ionic solids.

+

++

+

---

--

Cl-

Na+

Ions in solution.

- +

δ+

δ-

δ+

δ-

δ+

δ-δ+

δ-

δ+δ-δ

+

δ-

δ+

δ-

δ+

δ-

O

HH

Most electronegat

ive

δ+

δ-Oδ-

Hδ+Hδ+

Polar molecule

s

Hydrated ions

Dissolving.

-δ+

δ--

--

-

+

+

+

+δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ- δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

δ+

δ-

Some bonds broken

Some bonds made

---

-

+

+

+

+

-

Some bonds broken

Some bonds made

---

-

+

+

+

-

+

Some bonds broken

Some bonds made

Dissolving.Some bonds broken

Some bonds made

Endothermic

Exothermic

+

++

+

--

-

-

-

What is this?

ΔHLE

ΔHhyd(cat)-ΔHLE

ΔHsolΔHhyd(an)

What is this?

ΔHLE

ΔHhyd(cat)-ΔHLE

ΔHsolΔHhyd(an)

+

++

+

---

--

Exo or endo?

-ΔHLE+

++

+

---

--

---

-

+

+

+

+

-What is this?

ΔHLE

ΔHhyd(cat)-ΔHLE

ΔHsolΔHhyd(an)

---

-

+

+

+

+

-Exo or endo?

ΔHhyd(an)

---

-

+

+

+

-

+

What is this?

ΔHLE

ΔHhyd(cat)-ΔHLE

ΔHsolΔHhyd(an)

---

-

+

+

+

-

+

Exo or endo?

ΔHhyd(cat)

Solute + solvent

Gaseous ions

Solution

enthalpy

ΔHsolution

-ΔHLE

ΔHhyd(cat)

ΔHhyd(an)

-ΔHLE + ΔHhyd(cat) + ΔHhyd(an)ΔHsolution =

Solute + solvent

Gaseous ions

Solution

enthalpy

ΔHsolution

-ΔHLE

ΔHhyd(cat)

ΔHhyd(an)

ΔHsolution = Exo or endo? Endo

Solute + solvent

Gaseous ions

Solution

enthalpy

ΔHsolution

-ΔHLE

ΔHhyd(cat)

ΔHhyd(an)

ΔHsolution =

EndoWon’t dissolve

Solute + solvent

Gaseous ions

Solution

enthalpy

ΔHsolution

-ΔHLE

ΔHhyd(cat)

ΔHhyd(an)

ΔHsolution = Exo or endo? Exo

Solute + solvent

Gaseous ions

Solution

enthalpy

ΔHsolution

-ΔHLE

ΔHhyd(cat)

ΔHhyd(an)

ΔHsolution = Will dissolve Exo

Solute + solvent

Gaseous ions

Solution

enthalpy

ΔHsolution

-ΔHLE

ΔHhyd(cat)

ΔHhyd(an)

Slightly endoMay dissolve

Entropy!

Finally…. (Tables 5 and 7)

Ion Ionic radius

Water molecules attached

Na+

2,8,8

0.098nm

5

Mg2+

2,8,815

Al3+

2,8,8

0.057nm

26

0.078nm

+

2+