1 / 52

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.

francis-mcneil
Download Presentation

Should we control a chemical that:

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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.

More Related