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

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

What is the chemical? G Dihydrogen monoxide G Otherwise known as H 2 O G Dihydrogen monoxide G Otherwise known as H 2 O

Chapter 3 Water and the Fitness of the Environment

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

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

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

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

Water transport in trees uses Cohesion and Adhesion

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

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

Heat G Total quantity of kinetic energy due to molecular motion.

Temperature G Measures the average speed of the molecules.

Celsius Scale G Will be used for most of our temperature measurements. G O o C - water freezes G 100 o C - water boils G 37 o C - human body G Will be used for most of our temperature measurements. G O o C - water freezes G 100 o C - water boils G 37 o C - human body

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

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

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

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

Solids and Liquids WaterBenzene Floats Sinks

Solid LiquidGas States of Matter

Result G Aquatic life can live under ice.

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

Solution G Homogeneous mixture of two or more substances.

Solvent G The dissolving agent. G The material in the greater quantity. G The dissolving agent. G The material in the greater quantity.

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

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

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

Without Water Life Would Not Be Possible!!

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

Moles G The molecular weight of a substance in grams. G One Avogadro’s number of molecules X G The molecular weight of a substance in grams. G One Avogadro’s number of molecules X 10 23

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

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

Dissociation of Water G Water can sometimes split into two ions. G In pure water the concentration of each ion is M G Water can sometimes split into two ions. G In pure water the concentration of each ion is M

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

Acids G Materials that can release H + G Example: HCl HCl H + + Cl - G Materials that can release H + G Example: HCl HCl H + + Cl -

Acid Rain

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

Neutrals G Materials that are neither acids nor bases.

pH Scale G A logarithmic scale for showing H + concentration pH = - log [H + ] G A logarithmic scale for showing H + concentration pH = - log [H + ]

pH Scale

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

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

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

Buffers G Materials that have both acid and base properties. G Resist pH shifts. G Cells and other biological solutions often contain buffers to prevent damage. G Materials that have both acid and base properties. G Resist pH shifts. G Cells and other biological solutions often contain buffers to prevent damage.

Summary G Be able to discuss the properties of water. G Be able to measure solution concentrations in Molarity. G Be able to work pH scale questions. G Be able to discuss the properties of water. G Be able to measure solution concentrations in Molarity. G Be able to work pH scale questions.