Please collect ONE clicker each from the front.

1. 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.

2. Reduced Interaction of chains with water Hydrophobic interactions between chains 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.) • 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. at the c.m.c.

3. Blackman Figure 22.4 Blackman Figure 22.3 Soap 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.

4. Detergents • Artificial soaps are known as detergents • Most widely used class of detergents used are the alkylbenzenesulfonates(with –SO3- group) • Fabric softener are often quaternary ammonium salts

5. “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+

6. Soaps are produced by saponification: the hydrolysis of lipids to glycerol and salts of fatty acids (carboxylate salts = soaps) by KOH or NaOH. KOH carboxylate salt glycerol Polar-ionic head Lipids Figure from Silberberg, “Chemistry”, McGraw Hill, 2006. • Lipids are broadly defined as any amphiphilic, naturally-occurring 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 • Fats that are esters of glycerol are called triglycerides. Hydrophobic tail

7. Head group Tail group air water Self-Assembly in Lipids • In the self-assembly of surfactants and lipids, hydrophobic interactions are important A lipid is an amphiphilic molecule, but rarely exists as a monomer. Lipid bilayer Inverse micelle (in nonpolar solvent) monolayer Micelle

8. Phospholipids Phospatidylcholine hydrophilic • 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. Apolar hydrophobic Long hydrophobic tails a bilayer Polar head

9. 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; multilamellar vesicles unilamellar vesicles (liposomes); highly stable, can be used as drug and enzyme delivery systems

10. Cell Membrane Figure from Silberberg, “Chemistry”, McGraw Hill, 2006. • 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. Ca. 8 nm thick

11. 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 two-dimensional 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. Figure from Silberberg, “Chemistry”, McGraw Hill, 2006.

12. CHEM1612 - PharmacyWeek 13: Review of Concepts Dr. SiegbertSchmid School of Chemistry, Rm 223 Phone: 9351 4196 E-mail: siegbert.schmid@sydney.edu.au

13. 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

14. CHEM1109 – Chemistry for Life Sciences • Solubility • Oxidation Numbers • Complexes • Redox Reactions • Electrochemical cells • Electrolysis • Electrodes • Chemical Kinetics • Radiochemistry • Colloid Chemistry

15. 3 of 250 5 1. How did you get to Uni today? • On foot • By bike • By public transport (train, bus, ferry) • By car • With my chauffeured limousine • Other

16. 5 of 250 0 2. What degree are you enrolled in? • Bachelor of Science • Bachelor of Medical Science • Bachelor of Pharmacy • Bachelor of Arts • Exercise & Sports Science • Bachelor of Health Science • Physiotherapy • Other

17. 2 of 250 5 3. What is the expression for the solubility product constant of Ca3(PO4)2 ? • Ksp = [Ca2+] [PO43-] • Ksp = [3 Ca2+]3[2 PO43-]2 • Ksp = [Ca2+]3[PO43-]2 • Ksp = [Ca2+][PO43-] Correct

18. 3 of 250 3 4. Which of the following statements regarding the solubility of MnS is correct? • 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. • The solubility of MnS does not depend on temperature. • In all conditions [Mn2+] is different from [S2-]. Correct

19. 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- + OH- Adding acid, takes away some of the OH- and moves the reaction towards the right (increasing solubility).

20. 2 of 250 5 5. Referring to the reaction PbO (s) + CO (g) → Pb (s)+ CO2(g), which of the following statements is correct? • Pb in PbO is oxidised by the oxygen. • This is not a redox reaction. • PbO is the reducing agent. • CO2 is the oxidising agent. • Pb in PbO is reduced by the CO. Correct

21. 2 of 250 4 6. How is an aqueous solution affected if we dissolve in it a nitrate of a cation such as Fe3+, Cr3+ or Al3+? • The solution is unaffected. • The pH of the solution increases. • These nitrates are insoluble in water. • The pH of the solution decreases. • The nitrates form complexes with water. Correct

22. Acidic solution 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. 5 bound H2O molecules 1 bound OH- (overall charge reduced by 1) 6 bound H2O molecules

23. 4 of 250 2 7. What is the formula of the coordination complex hexaamminecobalt(III) tetrachloroferrate(III)? • [6Co(NH3)][4FeCl] • [Co(NH3)6][FeCl4] • [Co(NH3)6][FeCl4]3 • [Co3(NH3)6][Fe3Cl4] • [FeCl4]3 [Co(NH3)6] Correct

24. 4 of 250 2 8. What is the missing particle for the following nuclear decay process? Correct

25. Voltmeter Salt bridge Cu Zn Zn2+ Cu2+ 2 of 250 0 9. Which of the following statements regarding this electrochemical cell is correct? E0Zn=-0.76 V; E0Cu =0.34 V. • 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

26. 2 of 250 1 10. How does temperature affect the kinetics of a reaction? • 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. • Increasing the temperature increases the reaction rate because it decreases the value of the activation energy. Correct

27. 2 of 250 2 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) • 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

28. 1 of 250 5 12. Calculate the rate of production of NO2 for the reaction: 2 N2O5 → 4 NO2 + O2knowing that the rate of consumption of N2O5 is - 5.00·10-6 M s-1. • 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

29. 3 of 250 :00 13. Which of the following systems is an example of a sol? • Mist • Milk • Paint • Mayonnaise Correct

30. 0 of 250 :04 14. Identify the following symbol as an element and number its protons, neutrons and electrons: . • 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

31. 2 of 250 :02 15. What geometry and what kind of isomers does the complex [Co(NH3)4Cl2]+ have? • Square planar geometry and no isomers. • Tetrahedral geometry and one linkage isomer. • Octahedral geometry and two geometric isomers. • Square planar geometry and two geometric isomers. Correct

32. Answer

33. Summary • You should now… • RETURN YOUR CLICKER!! • Revise all notes • Work through past exam papers • See Duty Tutor or myself for help • (sooner rather than later) • Good luck in your exams!