1. Seawater Chemistry 003

2. Pure substances that cannot be broken down into simpler chemical entities by ordinary chemical reactions. Elements Periodic Table 112 known elements

4. An element is composed of atoms (0.1-1 nm in diameter) Atom  cluster of small particles (proton, neutron, electron)

5. Protons (p + ) Neutrons (n o ) Electrons (e - )

6. proton neutron electron hydrogen atom helium atom carbon atom 1p, 0n, 1e-2p, 2n, 2e- 6p, 6n, 6e-

7. atomic number: number of p; #p = #e- 2 He  2e- and 2p He

8. atomic mass (atomic wt.) : sum of masses of p+n He  2p + 2n, atomic mass = 4 4 2 He He p + n e-

9. p = n = e- = Atomic number = Atomic mass = C Carbon Atom

10. O16O17O18 stable isotopes Isotope atoms that differ in the number of neutrons 16 8 O 18 8 O 17 8 O #p #p+n O

11. Major Elements Comprising the Biological Molecules of Living Things C arbonC arbon H ydrogenH ydrogen O xygenO xygen N itrogenN itrogen P hosphorusP hosphorus S ulfurS ulfur

12. Other Major Elements of Living Things Calcium (Ca)Calcium (Ca) Potassium (K)Potassium (K) Chlorine (Cl)Chlorine (Cl) Magnesium (Mg)Magnesium (Mg)

13. Some Important Trace Elements of Living Things Boron (B)Boron (B) Cobalt (Co)Cobalt (Co) Iron (Fe)Iron (Fe) Copper (Cu)Copper (Cu) Fluorine (F)Fluorine (F) Zinc (Zn)Zinc (Zn)

14. Molecule Two or more atoms held together by chemical bonds OxygenO 2 NitrogenN 2 AmmoniaNH 3 Carbon DioxideCO 2 WaterH 2 O MethaneCH 4 GlucoseC 6 H 12 O 6

15. Carbohydrates: C 6 H 12 O 6 (glucose) Lipids: C 3 H 8 O 3 (glycerol) + 3C 16 H 32 O 2 (fatty acids) Proteins: COOH-NH 2 Nucleic Acids: sugar, PO 4, N 2 containing base Organic Molecules

16. Compound Binding two or more different kinds of elements together NaCl CH 4 C 6 H 12 O 6

17. Ion An atom that has either gained or lost electrons such that it exhibits a net charge Na+ Cl-

18. Sodium (Na) Atom 11 P + 12 N o

19. Sodium (Na + ) Ion 11 P + 12 N o

20. Chlorine (Cl) Atom 17 P + 18 N o

21. Chloride (Cl - ) Ion 17 P + 18 N o

22. HydrogenH + PotassiumK + FluorideF - CalciumCa +2 MagnesiumMg +2 HydroxideOH -HydroxideOH - BicarbonateHCO 3 -BicarbonateHCO 3 - NitrateNO 3 -NitrateNO 3 - PhosphatePO 4 -3PhosphatePO 4 -3

23. Ionic Covalent Hydrogen

24. Transfer of electron 17 P + 18 N o 11 P + 12 N o

25. electron sharing O H H

26. Between Water Molecules Covalent bond Hydrogen bond

27. Boiling Point: 100 o C Freezing Point: 0 o C Density: 1g/cm 3 Properties of Water gasliquid solid

28. The formation of ice As water cools to 4°C: –Molecules slow –Water contracts –Density increases Below 4°C: –Hydrogen bonds form –Water expands As water freezes: –Expands by 9%

29. IceDensity vs Temp ( o C)

30. Properties of Water 1.High heat capacity 2.High heat of vaporization 3.High Surface tension 4.Polarity solvent properties

31. The ocean moderates coastal temperatures Water has high heat capacity, so it can absorb (or release) large quantities of heat without changing temperature Moderates coastal temperatures

32. The ocean moderates coastal temperatures Hawaii Average High and Low Temperature Hawaii Average Ocean Water Temperature

33. Interconnections of water molecules Polarity causes water molecules to form weak (hydrogen) bonds between water molecules Water sticks to itself and to other substances Allows water to be the universal solvent

34. Water as a solvent Water dissolves table salt (NaCl) by attracting oppositely charged particles Pulls particles out of NaCl structure to dissolve it

35. Water has a high surface tension

36. Water in the 3 states of matter Latent (hidden) heat = energy that is either absorbed or released as water changes state

37. Properties of Seawater Heat capacity: Heat capacity with salinity Evaporation: Evaporates more slowly than fw Specific gravity: Pure water density = 1.000 g/cm 3 Seawater (2 o C) density = 1.028 g/cm 3 Seawater’s Boiling Point: As salinity, the boiling point

38. When NaCl dissolves, each ion becomes hydrated

39. Seawater’s Freezing Point: As salinity, the freezing point Salt is an antifreeze- doesn’t freeze until -2 o C ( @ 35 o / oo ) Lattice structure of an ice crystal Sea ice (pancake ice)

40. Salt IonIons in sw ( 0 / 00 ) Cl - 18.980 Na + 10.556 SO 4 2- 2.649 Mg 2+ 1.272 Ca 2+ 0.400 K + 0.380 HCO 3- 0.140 Br - 0.065 H 3 BO 3 0.026 Sr 2+ 0.013 F - 0.001 Total34.38

41. Na + - Weathering of crustal rock Cl - - from the mantle by way of volcanic vents and outgassing from mid-ocean rifts Mg ++ - mid ocean rifts

42. White sections represent warm surface currents. Purple sections represent deep cold currents

45. Acids HCL  H + + Cl - Proton donor, i.e., they donate H + ions HCl is a strong acid with a pH 1-2

46. Bases Na + + OH -  NaOH NH 3 + H +  NH 4 OH - + H +  H 2 O HCO 3 +H +  H 2 CO 3 Proton acceptor, i.e., they take up H+ ions NaOH is a strong base ~pH 12

47. Neutralization HCl + NaOH  H 2 O + NaCl

48. Buffer- resists dramatic changes in pH; ex. tums, rolaids…buffers stomach acid

49. Acids HCL  H + + Cl - Proton donor, i.e., they donate H + ions HCl is a strong acid with a pH 1-2

50. Bases Na + + OH -  NaOH NH 3 + H +  NH 4 OH - + H +  H 2 O HCO 3 - +H +  H 2 CO 3 Proton acceptor, i.e., they take up H+ ions NaOH is a strong base ~pH 12

51. Neutralization- HCl + NaOH  H 2 O + NaCl Buffer- resists dramatic changes in pH; ex. tums, rolaids…buffers stomach acid Neutralization & Buffers

52. pH Scale Acidic0-6 Neutral7 Basic (alkaline)8-14 Type of Solution pH Value 0-14

53. pH Scale Logarithmic scale

54. Depth (m) Concentration of dissolved gas (ppm) 0 500 1000 1500 2000 O 2 CO 2 90 94 98 102 106 110 1.5 3.0 4.5 6.0 7.5 CO 2 O2O2 O 2 and CO 2 vs ocean depth Compensation depth

55. Carbon Dioxide System in the Ocean Respiration Photosynthesis C 6 H 12 O 6 +6O 2 6CO 2 + 6H 2 O 6CO 2 + 6H 2 O C 6 H 12 O 6 +6O 2 Air Water CO 2 gas

56. CO 2 + H 2 O ↔ H 2 CO 3 ↔ HCO 3 - + H + ↔ CO 3 2- + 2H + By-product of respiration carbonic acid bicarbonate carbonate The addition of CO 2 makes water acidic The effects of pH in an ocean system

57. Carbonate buffer Seawater too basic: H 2 CO 3 HCO 3 - + H + pH drops Seawater too acidic: HCO 3 - + H + H 2 CO 3 pH rises

58. Ocean Acidity

59. Global Ocean Acidity.

60. Consequences of Ocean Acidity Animals with CaCO 3 skeletons affected Plankton Corals Mollusks Fish http://news.bbc.co.uk/2/hi/science/nature/7933589.stm Fisheries

61. In a high CO 2 world, the ocean will be… More acidic More stratified More oligotrophic, but better light conditions Less oxygenated Consequences of Ocean Acidity

62. Inquiry 1.How many neutrons in 7 N? 2.Why do all the oceans have relatively the same proportion of salinity? 3.At what temperature is fw most dense? 4.Of the following pH’s which is most acidic? 3762 5. Why are there no plants at the compensation depth? 6. Why can a water strider walk on water? 7. Besides temperature and salinity, what physical factor effects thermohaline circulation? 8. What is the oceans most dense sea water called? 14