II III I Hydrogen Bonding and The Nature of Solutions Ch. 13 & 14 - Solutions 1

II

III

I Hydrogen Bonding and The Nature of Solutions

Ch. 13 & 14 - SolutionsCh. 13 & 14 - Solutions

1

Hydrogen BondingHydrogen Bonding

A hydrogen atom that is bonded to a highly electronegative atom (such as oxygen) is attracted to an unshared pair of electrons of an electronegative atom in a nearby molecule

2

Hydrogen BondingHydrogen Bonding

Due to the small size of the hydrogen atom, it can become very close to an unshared pair of electrons on the adjacent molecule

Compounds with this type of force have unusually high boiling points.

3

Hydrogen bondingHydrogen bonding

Hydrogen bonding is what gives water its unusual properties such as :• High boiling point/ melting point • Great surface tension• Amphoteric (can be an acid or a base.)• High polarity• Known as “the universal solvent”

4

Hydrogen bondingHydrogen bonding

5

A. DefinitionsA. Definitions

Solution - Solution - homogeneous mixture

Solvent Solvent - present in greater amount

Solute Solute - substance being dissolved

6

A. DefinitionsA. Definitions

Solute Solute - KMnO4Solvent Solvent - H2O

7

B. SolvationB. Solvation

Solvation – Solvation – the process of dissolving

solute particles are separated and pulled into solution

solute particles are surrounded by solvent particles

8

B. SolvationB. Solvation

StrongElectrolyte

Non-Electrolyte

solute exists asions only

- +

salt

- +

sugar

solute exists asmolecules

only

- +

acetic acid

WeakElectrolyte

solute exists asions and

molecules DISSOCIATION IONIZATION

View animation online.9

B. SolvationB. Solvation

DissociationDissociation• separation of an

ionic solid into aqueous ions

NaCl(s) Na+(aq) + Cl–(aq)

10

B. SolvationB. Solvation

IonizationIonization• breaking apart of

some polar molecules into aqueous ions

HNO3(aq) + H2O(l) H3O+(aq) + NO3–(aq)

11

B. SolvationB. Solvation

Molecular Molecular SolvationSolvation• molecules

stay intact

C6H12O6(s) C6H12O6(aq)

12

B. SolvationB. Solvation

NONPOLAR

NONPOLAR

POLAR

POLAR

““Like Dissolves Like”Like Dissolves Like”““Like Dissolves Like”Like Dissolves Like”

13

B. SolvationB. Solvation

Soap/DetergentSoap/Detergent• polar “head” with long nonpolar “tail”• dissolves nonpolar grease in polar water

14

C. SolubilityC. Solubility

SATURATED SOLUTION

no more solute dissolves

UNSATURATED SOLUTIONmore solute dissolves

SUPERSATURATED SOLUTION

becomes unstable, crystals form

concentration15

C. SolubilityC. Solubility

SolubilitySolubility• maximum grams of solute that will

dissolve in 100 g of solvent at a given temperature

• varies with temp• based on a saturated solution

16

C. SolubilityC. Solubility

Solubility CurveSolubility Curve• shows the

dependence of solubility on temperature

17

C. SolubilityC. Solubility

Solids are more soluble at...Solids are more soluble at...• high temperatures.

Gases are more soluble at...Gases are more soluble at...• low temperatures &• high pressures

(Henry’s Law).• EX: nitrogen narcosis,

the “bends,” soda18