Please collect ONE clicker each
from the front.
We will use them for a review of
multiple choice questions.
Please return clickers at the end
of the lecture.
Self-Assembly: Micelles



As a surfactant is added to water, the molecules adsorb at the air/liquid
interface, but otherwise are free in solution.
Above a certain conc., they spontaneously aggregate into micelles.
This occurs at the CRITICAL MICELLE CONCENTRATION (c.m.c.)
at the
c.m.c.

Reduced
Interaction
of chains
with water
Hydrophobic
interactions
between
chains
A “soap” solution contains both individual surfactants dispersed in water
and aggregates (micelles). Thus a soap-water mixture is a suspension
of micelles in water. Because the relatively large micelles scatter light
(colloidal), soapy water looks cloudy.
Soap
Blackman Figure 22.4
Blackman Figure 22.3
Much of what we call dirt is non-polar. Grease for example consists of long chain
hydrocarbons.

However water, the solvent most commonly available to us is very polar and
will not dissolve ‘greasy dirt’

Soap can be viewed as an emulsifying agent, since it acts to suspend the
normally incompatible grease in the water.

Because of this ability to assist water in ‘wetting’ and suspending nonpolar
materials, soap is called a wetting agent or surfactant.
Detergents

Artificial soaps are known as detergents

Most widely used class of detergents used are the alkylbenzene
sulfonates (with –SO3- group)

Fabric softener are often quaternary ammonium salts
“Hard” and “Soft” Water

“Hard water” contains high amounts of divalent ions such as Ca2+,
Mg2+, Fe2+.
The disadvantage of soaps is that the anions form precipitates with
the cations like Ca2+ and Mg2+. This forms a scum and reduces the
soaps’ efficiency.

Ca2+ + 2 C17H35COONa(aq) → (C17H35COO)Ca (s) + 2 Na+

Lipids are broadly defined as any amphiphilic, naturallyoccurring molecules. The term is also used more
specifically to refer to fatty-acids and their derivatives, as
well as other fat-soluble sterol-containing metabolites such
as cholesterol.





fats
phospholipids (with a organophosphate group)
waxes
steroids
Hydrophobic
tail
Fats that are esters of glycerol are
called triglycerides.
Soaps are produced by saponification:
the hydrolysis of lipids to glycerol and
salts of fatty acids (carboxylate salts =
soaps) by KOH or NaOH.
Figure from Silberberg, “Chemistry”,

McGraw Hill, 2006.
Lipids
Polar-ionic
head
KOH
carboxylate salt
glycerol
Self-Assembly in Lipids

In the self-assembly of surfactants and lipids, hydrophobic
interactions are important
Head
group
Tail
group
A lipid is an amphiphilic molecule,
but rarely exists as a monomer.
air
water
monolayer
Micelle
Inverse micelle
(in nonpolar
solvent)
Lipid bilayer
Phospholipids
Phospatidylcholine
hydrophilic
Apolar
hydrophobic
a bilayer
Long hydrophobic tails
Polar head

Phospholipids are similar in structure to fats in that they are esters
of glycerol. However unlike fats they contain only two fatty acids.
The third ester linkage involves a phosphate group, which gives
phospholipids two distinct parts:
 long non-polar tail
 polar substituted phosphate “head”

Phospholipids tend to form bilayers in aqueous solution with the
tails in the interior and the polar heads interfacing with the polar
water molecules.
Self-assembly in Phospholipids


Phospholipids prefer to form bilayer structures in aqueous solution
because their two fatty acid chains do not pack well;
Phospholipids can form either unilamellar vesicles (liposomes) or
multilamellar vesicles;
unilamellar vesicles (liposomes);
highly stable, can be used as drug
and enzyme delivery systems
multilamellar vesicles




McGraw Hill, 2006.
Figure from Silberberg, “Chemistry”,
Cell Membrane
Ca. 8 nm thick
A cell membrane is a bilayer of phospholipids, embedded with
various proteins, and protects the cell from the extracellular fluid
that surrounds it.
Allows nutrients and other necessary chemicals to enter the cell
and waste products to leave, through the proteins that act as
pumps, gates, and channels.
Biological membranes are sites of biochemical reactions that
include photosynthesis, electron transfer, oxidative phosphorylation;
Facilitate cell motion; provide cell recognition and cell fusion.
Fluid Mosaic Model
The most widely accepted model of this transfer of nutrients and waste
is called the fluid mosaic mode, proposed by S. J. Singer and G. L.
Nicolson, in 1972.

The phospholipid bilayer is a fluid matrix: the bilayer is a twodimensional solvent, lipids and proteins can undergo rotational and
lateral movement

Small uncharged molecules such as water,
oxygen and carbon dioxide diffuse freely
through the bilayer, while other substances
pass through “gates and passages”
provided by specific proteins embedded
in the membrane.
McGraw Hill, 2006.
Figure from Silberberg, “Chemistry”,

CHEM1612 - Pharmacy
Week 13: Review of Concepts
Dr. Siegbert Schmid
School of Chemistry, Rm 223
Phone: 9351 4196
E-mail: siegbert.schmid@sydney.edu.au
Unless otherwise stated, all images in this file have been reproduced from:
Blackman, Bottle, Schmid, Mocerino and Wille,
Chemistry, John Wiley & Sons Australia, Ltd. 2008
ISBN: 9 78047081 0866
CHEM1109 – Chemistry for Life Sciences
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Solubility
Oxidation Numbers
Complexes
Redox Reactions
Electrochemical cells
Electrolysis
Electrodes
Chemical Kinetics
Radiochemistry
Colloid Chemistry
1. How did you get to Uni today?
67%
33%
0%
0%
0%
0%
1.
2.
3.
4.
5.
6.
On foot
By bike
By public transport (train, bus, ferry)
By car
With my chauffeured limousine
Other
2. What degree are you enrolled in?
20%
40%
20%
1.
0%
0%
0%
0%
4.
20%
8.
2.
3.
5.
6.
7.
Bachelor of Science
Bachelor of Medical Science
Bachelor of Pharmacy
Bachelor of Arts
Exercise & Sports Science
Bachelor of Health Science
Physiotherapy
Other
3. What is the expression for the solubility
product constant of Ca3(PO4)2 ?
50%
50%
0%
0%
1.
2.
3.
4.
Ksp = [Ca2+] [PO43-]
Ksp = [3 Ca2+]3[2 PO43-]2
Ksp = [Ca2+]3[PO43-]2
Ksp = [Ca2+][PO43-]
Correct
4. Which of the following statements
regarding the solubility of MnS is correct?
33%
67%
1.
0%
0%
3.
0%
2.
4.
5.
pH has no effect on the solubility of MnS.
MnS is more soluble at pH 12 than at pH 7.
MnS is more soluble at pH 4 than at pH 7.
Correct
The solubility of MnS does not depend on temperature.
In all conditions [Mn2+] is different from [S2-].
Answer: 3
In water solution S2- is basic and takes H+ leaving OH- ions in solution.
Therefore, the overall dissolution of insoluble MnS is:
MnS + H2O → Mn2+ + HS- + OHAdding acid, takes away some of the OH- and moves the reaction
towards the right (increasing solubility).
5. Referring to the reaction
PbO (s) + CO (g) → Pb (s)+ CO2(g),
which of the following statements is correct?
50%
1.
50%
2.
0%
3.
0%
4.
0%
5.
Pb in PbO is oxidised by the oxygen.
This is not a redox reaction.
PbO is the reducing agent.
CO2 is the oxidising agent.
Correct
Pb in PbO is reduced by the CO.
6. How is an aqueous solution affected if we
dissolve in it a nitrate of a cation such as Fe3+,
Cr3+ or Al3+?
50%
0%
0%
50%
0%
1.
2.
3.
4.
5.
The solution is unaffected.
The pH of the solution increases.
These nitrates are insoluble in water.
The pH of the solution decreases.
Correct
The nitrates form complexes with water.
Answer: Acidity of Aqueous Transition Metal Ions
A small and multiply-charged metal ion acts as an acid in water, i.e. the
hydrated metal ion transfers an H+ ion to water.
6 bound H2O molecules
5 bound H2O molecules
1 bound OH(overall charge reduced by 1)
Acidic
solution
7. What is the formula of the coordination
complex hexaamminecobalt(III)
tetrachloroferrate(III)?
25%
25%
0%
25%
25%
1.
2.
3.
4.
5.
[6Co(NH3)][4FeCl]
[Co(NH3)6][FeCl4]
[Co(NH3)6][FeCl4]3
[Co3(NH3)6][Fe3Cl4]
[FeCl4]3 [Co(NH3)6]
Correct
8. What is the missing particle for the
following nuclear decay process?
14
6
50%
1.
25%
2.
0%
3.
25%
4.
0%
5.
0
1
1
0
0
1
C

n


4
2
He
14
7
N?
Correct
9. Which of the following statements regarding this
electrochemical cell is correct? E0Zn=-0.76 V;
E0Cu =0.34 V.
Voltmeter
Salt bridge
Cu
Zn
Zn2+
100%
1.
0%
2.
0%
3.
0%
4.
Cu2+
Zn is oxidised at the anode and Cu is reduced at the cathode.
Electrons flow from left to right.
Zn is oxidised at the cathode and Cu is reduced at the anode.
Electrons flow from left to right.
Zn is oxidised at the anode and Cu is reduced at the cathode.
Electrons flow from right to left.
Zn is oxidised at the cathode and Cu is reduced at the anode.
Electrons flow from right to left.
Correct
10. How does temperature affect the
kinetics of a reaction?
100% 1.
2.
0%
3.
0%
4.
0%
0%
5.
Temperature does not affect the kinetics of most reactions.
Increasing the temperature increases the reaction rate because it
increases the amount of collisions occurring between reactant molecules.
Increasing the temperature only increases the reaction rate of exothermic
reactions.
Increasing the temperature increases the reaction rate because it
increases the fraction of collisions with enough energy to exceed the
activation energy.
Correct
Increasing the temperature increases the reaction rate because it
decreases the value of the activation energy.
11. Which of the following statements
concerning the solubility of a mixture of NiS
and CuS of equal initial concentrations is true ?
(Ksp(NiS) = 1·10-22; Ksp(CuS) = 4·10-36)
0%
100%
0%
0%
0%
1.
2.
3.
4.
5.
NiS will precipitate first from a mixture of the two salts.
Both salts are highly soluble in water.
The presence of NiS increases the solubility of CuS.
It is not possible to selectively precipitate the two salts.
CuS will precipitate first from a mixture of the two salts.
Correct
12. Calculate the rate of production of NO2 for the reaction:
2 N2O5 → 4 NO2 + O2
knowing that the rate of consumption of N2O5 is - 5.00·10-6 M s-1.
100%
1.
0%
2.
0%
3.
0%
4.
Rate of production of NO2 = 0.00001 M s-1
Rate of production of NO2 = 1.00·10-5 M s-1
Rate of production of NO2 = 20 ·10-6 M s-1
Rate of production of NO2 = 2.500·10-5 M s-1
Correct
13. Which of the following systems is an
example of a sol?
0%
1.
67%
2.
0%
3.
33%
4.
Mist
Milk
Paint
Mayonnaise
Correct
14. Identify the following symbol as an
element and number its protons,
30
neutrons and electrons: 14 X .
1.
2.
3.
4.
5.
Zn, neutrons=30, protons=14; electrons = 16
Si, neutrons=16; protons=14; electrons=14
S, neutrons=14; protons=16; electrons=16
Si, neutrons=14; protons=16; electrons=16
Zn, neutrons= 30; protons=14; electrons=14
Correct
15. What geometry and what kind of isomers
does the complex [Co(NH3)4Cl2]+ have?
50%1.
50%2.
0% 3.
0% 4.
Square planar geometry and no isomers.
Tetrahedral geometry and one linkage isomer.
Correct
Octahedral geometry and two geometric isomers.
Square planar geometry and two geometric isomers.
Answer
Summary
You should now…
1. RETURN YOUR CLICKER!!
2. Revise all notes
3. Work through past exam papers
4. See Duty Tutor or myself for help
(sooner rather than later)
Good luck in your exams!