Antoine Lavoisier. Tax Collector. Chemist. Geologist. Metric System.

1. Antoine Lavoisier. Tax Collector. Chemist. Geologist. Metric System. Contemporary with Dr. Guiotine.

8. The Source of the Ocean’s Salts Is the ocean chemistry due to weathering of crustal rocks? No. River water is a dilute solution of calcium (Ca2+), bicarbonate and magnesium ions. The ocean is primarily sodium and chloride ions.

9. Landlocked seas like Mono lake get saltier with age. Why doesn’t the ocean?

10. Mono Lake is concentrated river water:

11. Calcium (rivers) + Carbonate (atmosphere) makes Calcium carbonate. Ca2+ + CO32-> CaCO3

12. Excess Volatiles: carbon dioxide, chlorine, sulfur, hydrogen, fluorine, nitrogen, water vapor. Due to outgassing of the upper mantle. The ocean’s solutes are hybrids of the two processes of weathering and outgassing. Sodium comes from the weathering of feldspars in granites; chloride comes from the mantle by way of volcanic vents and outgassing from mid oceanic rifts.

13. The Principle of Constant Proportions. The amount of solute may vary, but the ratio of major salts is always the same. The oceans are well mixed. This is also known as Forchhamer’s Principle.

15. Determining Salinity This is difficult to do by heating and evaporating. It is easy to do my measuring chloride ion in a test tube and using this formula: Salinity in parts per thousand (ppt) = 1.80655 X Chloride in ppt. Typical salinity is 34.7 ppt Salinometers and Conductance.

18. Mixing Time. All waters on earth will take about 1,600 years to mix.

19. Landlocked seas like Mono lake get saltier with age. Why doesn’t the ocean?

20. Demonstration of Flow Equilibrium • The rate that material enters a system is the same rate that material exits the system. The oceans are a system in chemical equilibrium with all materials that enter and exit the seas. Thus the oceans don’t get saltier!

21. Residence Time- The average length of time an atom of an element spends in the ocean. Residence Time = Amount of element in the ocean Rate the element is added to (or removed from) the ocean  Examples of elements being added -salts from the mantle due to volcanism -weathering of surface rocks Examples of elements being subtracted 1.     -minerals being bound into sediments 2.     -minerals being used by organisms such as shells and reefs 3. -subduction of minerals into the mantle

24. Conservative and Nonconservative Constituents Conservative elements have long residence times. (chloride, sodium, magnesium etc.) Nonconservative elements have short residence times. Biologically active elements- O2, CO2, silica, calcium, nitrates, phosphates Geologic active elements- aluminum is bound up in clays (kaolinite- “kaopectate”)

25. Dissolved Gases in the Ocean

27. “Like Dissolves in Like” Water Molecule Oxygen Molecule Nitrogen Molecule

28. Water Molecule Carbon Dioxide Molecule Carbon Dioxide Molecule dissolves easily in water. Why doesn’t it obey “Like Dissolves Like”?

29. Dissolved Gases in the Ocean In order of abundance- Nitrogen (N2), oxygen (O2), carbon dioxide (CO2) Gases dissolve most easily on cold water. Why does CO2 dissolve so much?

30. Oxygen gas dissolved in water. Oxygen is nonpolar, water is polar, so they don’t mix well. 6 parts per million in the ocean! Gills extract this gas by diffusion (high to low concentration). Carbon Dioxide gas dissolved in water. CO2 can dissolve in water even though it is nonpolar. It reacts chemically to form a variety of ions

31. The bicarbonate ion is an ion so it dissolves easily in water

32. Independent Work. Reading Outline 7.30 7.16 Study Guide through #23

33. Acid or Base is Measure on the pH scale

35. Demonstration Stress and Shift during dynamic equilibrium Writing: • Describe the stress applied to the aquarium and how the dynamic equilibrium shifted. 2. Describe the stress applied to the crystallization and dissolution of KNO3 salt last week. KNO3(s) + Energy ↔ K+ + NO3-.

36. Representing Chemical Dynamic EquilibriumAnswer the following about soft drinks. CO2(gas) + H20(liquid)↔ H2CO3(dissolved) • If pressure is added, what direction will the system shift? • If pressure is removed, what direction will the system shift? 3. If carbon dioxide increases, what direction will the system shift?

37. Carbonate System Equilibrium CO2 + H20 ↔ H2CO3 H2CO3 ↔ HCO3- + H+ H+ means acidic HCO3- + H+ ↔ CO3- + 2H+ Ca2+ + CO32- ↔ CaCO3 seashell “salt”

38. b

39. Soft drinks What will happen,if pH decreases, to the amount of CO32-? Why is this a problem to all life?

40. Ca2+ + CO32- ↔ CaCO3 seashell “salt”

41. Other Organisms that need Shells

42. Other Organisms that need Shells Pteropods. Snails that are “marine butterflies”. Base of many food webs.

43. Read and Outline 7.17 Complete the Study Guide Draw Figures 7.10 and 7.11 in your outline.

44. Acid/Base Indicator Lab and the Near Future of the Oceans • Trial Descrip. Color pH note • 1 • 2 • 3 • 4 • 5 Orangish Distilled water + phenol red =7 neutral Distilled water + p. red + baking soda Red >7 basic Yellow Trial 2 plus drops of acid acidic <7 Distilled water + p. red + 20 drops acid. acidic Yellow <7 basic Seawater + p. red + 20 drops acid Red! >7

45. Ocean chemistry is a buffered chemical system • Like blood, the ions present in the ocean prevent swings in pH. • This is good for living things. • However….

46. Seawater is a buffered chemical system.

47. Lab- ContinuedShifting gaseous CO2 into the Ocean…and back out. • Trial Descrip. Color pH note • 6 • 7 seawater + red + CO2 Yellow <7 seawater + red + CO2 24 hours later pink >7

48. Active Reading Assignment: The Darkening Sea • Paragraph Main Idea, People, Facts, Concept

49. Conductivity Lab • Given 10.0 grams of NaCl, 200 ml beaker, tap water and a conductivity tool; • Design an experiment to estimate the concentration of an unknown salinity. • Prepare the unknown sample and give the solution to Mr. Heaton • Obtain a sample estimate the concentration. Paragraph write-up.

50. Solubility of Gases • Given a 200 ml beaker and a gas supply, make a graph of dissolved oxygen vs. temperature.