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. Has been found in tumors of terminal cancer patients.
What is the chemical? Dihydrogen monoxide Otherwise known as H 2 O or Water.
Page 4 Chapter 3 Water and the Fitness of the Environment
Page 5 Question? What molecule is the most common in living cells? Water - most cells are % water.
Page 6 The Water Planet
Page 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.
Page 8 Liquid Water Is Cohesive Water sticks to water. Why? Because the polarity of water results in hydrogen bonding.
Page 9 Liquid Water is Adhesive Water sticks to other molecules. Why? Hydrogen bonding.
Page 10 Water transport in trees uses Cohesion and Adhesion
Page 11 Water Has A High Surface Tension The surface of water is difficult to stretch or break. Why? Hydrogen bonding.
Page 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.
Page 13 Heat Total quantity of kinetic energy due to molecular motion.
Page 14 Temperature Measures the average speed of the molecules.
Page 15 Celsius Scale Will be used for most of our temperature measurements. O o C - water freezes 100 o C - water boils 37 o C – average human body
Page 16 Water Stabilizes Temperature Water can absorb and store a huge amount of heat from the sun. Result - climate moderation (lake effect). Result - organisms are able to survive temperature changes.
Page 17 Fig. 3-5 San Diego 72° 40 miles Pacific Ocean 70s (°F ) 80s 90s 100s Santa Barbara 73° Los Angeles (Airport) 75° Burbank 90° San Bernardino 100° Riverside 96° Santa Ana 84° Palm Springs 106°
Page 18 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.
Page 19 Evaporative Cooling
Page 20 Result: Water cools organisms from excessive heat buildup. Why? Hydrogen bonding
Page 21 Water Expands When It Freezes The distance between water molecules INCREASES from the liquid to the solid form. Why? Hydrogen bonding
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Page 23 Solids and Liquids Water Benzene Floats Sinks
Page 24 Solid LiquidGas States of Matter
Page 25 Result Aquatic life can live under ice.
Page 26 Water Is A Versatile Solvent Water will form a solution with many materials. Why? Hydrogen bonding
Page 27 Solution Homogeneous mixture of two or more substances.
Page 28 Solvent The dissolving agent. The material in the greater quantity.
Page 29 Solute The substance that is dissolved. The material in the lesser quantity.
Page 30 Hydrophilic Materials Materials that dissolve in water. Hydro - water philic - to like or love Have ionic or polar regions on their molecules for H + bonds.
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Page 33 Hydrophobic Materials that repel water. Hydro - water phobic - to fear Have non-polar covalent bonds. Ex - lipids.
Page 34 Without Water Life Would Not Be Possible!!
Page 35 Solution Concentration Usually based on Molarity. Molarity - the number of moles of solute per liter of solution.
Page 36 Moles The molecular weight of a substance in grams. One Avogadro’s number of molecules X 10 23
Page 37 One Mole of each Sulfur Sugar Copper Sulfate Mercury Oxide Copper Sodium Chloride
Page 38 Comment AP Biology students should be able to calculate solutions in Molarity.
AP BIOLOGY Austin From Burris
Page 40 Homework Read Chapter 3, 4 Chapter 2 – today Lab – graphs, science practices and math Chapter 3 – Wed. 8/29 Chapter 4 – Fri. 8/31
Page 41 Dissociation of Water Water can sometimes split into two ions. In pure water the concentration of each ion is M
Page 42 Adding certain solutes disrupts the balance between the two ions. The two ions are very reactive and can drastically affect a cell.
Page 43 Acids Materials that can release H + Example: HCl HCl H + + Cl -
Page 44 Acid Rain
Page 45 Acid Rain
Page 46 Bases Materials that can absorb H + Often reduce H + by producing OH - Example: NaOH NaOH Na + + OH -
Page 47 Neutrals Materials that are neither acids nor bases.
Page 48 pH Scale A logarithmic scale for showing H + concentration pH = - log [H + ]
Page 49 pH Scale
Page 50 Example: For a neutral solution: [H + ] is or - log or - (-7) or 7
Page 51 pH Scale Acids: pH <7 etc. Bases: pH >7 etc. Each pH unit is a 10x change in H +
Page 52 Comment [H + ] + [OH - ] = 14 Therefore, if you know the concentration of one ion, you can easily calculate the other.
Page 53 Fig. 3-9 Neutral solution Acidic solution Basic solution OH – H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ Neutral [H + ] = [OH – ] Increasingly Acidic [H + ] > [OH – ] Increasingly Basic [H + ] < [OH – ] pH Scale Battery acid Gastric juice, lemon juice Vinegar, beer, wine, cola Tomato juice Black coffee Rainwater Urine Saliva Pure water Human blood, tears Seawater 9 10 Milk of magnesia Household ammonia Household bleach Oven cleaner
Page 54 Buffers Materials that have both acid and base properties. Resist pH shifts. Cells and other biological solutions often contain buffers to prevent damage.
Page 55 Chapter Summary Be able to discuss the properties of water. Be able to measure solution concentrations in Molarity. Be able to work pH scale questions.