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Should we control a chemical that:

Should we control a chemical that:. Causes excessive sweating and vomiting. Is a major component in acid rain. Can cause severe burns in its gaseous state. Accidental inhalation can kill you. Contributes to erosion. Decreases the effectiveness of car brakes.

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Should we control a chemical that:

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  1. Should we control a chemical that: • Causes excessive sweating and vomiting. • Is a major component in acid rain. • Can cause severe burns in its gaseous state.

  2. Accidental inhalation can kill you. • Contributes to erosion. • Decreases the effectiveness of car brakes. • Has been found in tumors of terminal cancer patients.

  3. What is the chemical? • Dihydrogen monoxide • Otherwise known as H2O

  4. Chapter 3Water and the Fitness of the Environment

  5. Question? What molecule Is the most common In living Cells? Water - most cells are 70 - 95% water.

  6. The Water Planet

  7. Properties Of Water • Be ready and able to discuss several of the following properties. • Focus on definitions and examples. • Review water structure and H-bonds from Chapter 2.

  8. Liquid Water Is Cohesive • Water sticks to water. • Why? Because the polarity of water results in hydrogen bonding.

  9. Liquid Water is Adhesive • Water sticks to other molecules. • Why? Hydrogen bonding.

  10. Water transport in trees uses Cohesion and Adhesion

  11. Water Has A High Surface Tension • The surface of water is difficult to stretch or break. • Why? Hydrogen bonding.

  12. Water Has A High Specific Heat • Specific Heat - the amount of heat needed to raise 1 g of the substance 1 degree C. • Why? Hydrogen bonding.

  13. Heat • Total quantity of kinetic energy due to molecular motion.

  14. Temperature • Measures the average speed of the molecules.

  15. Celsius Scale • Will be used for most of our temperature measurements. • O oC - water freezes • 100 oC - water boils • 37 oC - human body

  16. Water Stabilizes Temperature • Water can absorb and store a huge amount of heat from the sun. • Result - climate moderation • Result - organisms are able to survive temperature changes.

  17. Water Has A High Heat Of Vaporization • Heat of Vaporization: the quantity of heat a liquid must absorb for 1g of it to convert to a gaseous state.

  18. Evaporative Cooling

  19. Result: • Water cools organisms from excessive heat buildup. • Why? Hydrogen bonding

  20. Homework • Read chapter 3 • Lab 1 report – next lab period • Chapter 2 homework – today • Lab – Predator/Prey • Chapter 3 – Fri. 8/24 • Discussion Board – Fri. 8/24

  21. AP Biology Ben - Burris

  22. Water Expands When It Freezes • The distance between water molecules INCREASES from the liquid to the solid form. • Why? • Hydrogen bonding

  23. Solids and Liquids Water Benzene Floats Sinks

  24. States of Matter Liquid Gas Solid

  25. Result • Aquatic life can live under ice.

  26. Water Is A Versatile Solvent • Water will form a solution with many materials. • Why? Hydrogen bonding

  27. Solution • Homogeneous mixture of two or more substances.

  28. Solvent • The dissolving agent. • The material in the greater quantity.

  29. Solute • The substance that is dissolved. • The material in the lesser quantity.

  30. Hydrophilic Materials • Materials that dissolve in water. • Hydro - water • philic - to like or love • Have ionic or polar regions (polar covalent bonds) on their molecules for H+ bonds.

  31. Hydrophobic • Materials that repel water. • Hydro - water • phobic - to fear • Have non-polar covalent bonds. Ex - lipids.

  32. Solution Concentration • Usually based on Molarity. • Molarity - the number of moles of solute per liter of solution.

  33. Moles • The molecular weight of a substance in grams. • One Avogadro’s number of molecules. 6.02 X 1023

  34. One Mole of each Sugar Copper Sulfate Sulfur Mercury Oxide Sodium Chloride Copper

  35. Comment • AP Biology students should be able to calculate solutions in Molarity.

  36. Dissociation of Water • Water can sometimes split into two ions. • In pure water the concentration of each ion is 10-7 M

  37. Adding certain solutes disrupts the balance between the two ions. • The two ions are very reactive and can drastically affect a cell.

  38. Acids • Materials that can release H+ • Example: HCl HCl H+ + Cl-

  39. Acid Rain

  40. Acid Rain

  41. Bases • Materials that can absorb H+ • Often reduce H+ by producing OH- • Example: NaOH NaOH Na+ + OH-

  42. Neutrals • Materials that are neither acids nor bases.

  43. pH Scale • A logarithmic scale for showing H+ concentration pH = - log [H+]

  44. pH Scale

  45. Example: For a neutral solution: [H+] is 10-7 or - log 10-7 or - (-7) or 7

  46. Acids: pH <7 etc. • Bases: pH >7 etc. • Each pH unit is a 10x change in H+

  47. Comment • [H+] + [OH-] = 14 • Therefore, if you know the concentration of one ion, you can easily calculate the other.

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