Should we control a chemical that: G Causes excessive sweating and vomiting. G Is a major component...

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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.

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.

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?What is the chemical?

Dihydrogen monoxide

Otherwise known as H2O

Dihydrogen monoxide

Otherwise known as H2O

Chapter 3Water and the Fitness of

the Environment

Chapter 3Water and the Fitness of

the Environment

Question?Question?

What molecule Is the most common In living Cells?

Water - most cells are 70 - 95% water.

What molecule Is the most common In living Cells?

Water - most cells are 70 - 95% water.

Properties Of WaterProperties Of Water

Be ready and able to discuss several of the following properties.

Focus on definitions and examples.Review water structure and

Hydrogen bonds from Chapter 2.

Be ready and able to discuss several of the following properties.

Focus on definitions and examples.Review water structure and

Hydrogen bonds from Chapter 2.

Liquid Water Is CohesiveLiquid Water Is Cohesive

Water sticks to water.Why? Because the polarity of water

results in hydrogen bonding.

Water sticks to water.Why? Because the polarity of water

results in hydrogen bonding.

Liquid Water is AdhesiveLiquid Water is Adhesive

Water sticks to other molecules.Why? Hydrogen bonding.

Water transport in trees uses Cohesion and Adhesion

Water Has A High Surface Tension

The surface of water is difficult to stretch or break.

Why? Hydrogen bonding.

The surface of water is difficult to stretch or break.

Water Has A High Specific Heat

Specific Heat - the amount of heat needed to raise 1 g of the substance 1 degree C.

HeatHeat

Total quantity of kinetic energy due to molecular motion.

TemperatureTemperature

Measures the average speed of the molecules.

Celsius ScaleCelsius Scale

Will be used for most of our temperature measurements.

O oC - water freezes100 oC - water boils37 oC - human body

Will be used for most of our temperature measurements.

O oC - water freezes100 oC - water boils37 oC - human body

Water Stabilizes Temperature

Water can absorb and store a huge amount of heat from the sun.

Result - climate moderationResult - organisms are able to

survive temperature changes.

Water can absorb and store a huge amount of heat from the sun.

Result - climate moderationResult - organisms are able to

survive temperature changes.

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.

Result:Result:

Water cools organisms from excessive heat buildup.

Why? Hydrogen bonding

Water cools organisms from excessive heat buildup.

Water Expands When It Freezes

The distance between water molecules INCREASES from the liquid to the solid form.

Why?Hydrogen bonding

The distance between water molecules INCREASES from the liquid to the solid form.

Why?Hydrogen bonding

Solids and LiquidsSolids and Liquids

Water Benzene

Floats Sinks

Solid Liquid Gas

States of Matter

ResultResultAquatic life can live under ice.Aquatic life can live under ice.

Water Is A Versatile Solvent

Water will form a solution with many materials.

SolutionSolution

Homogeneous mixture of two or more substances.

SolventSolvent

The dissolving agent.The material in the greater

quantity.

The dissolving agent.The material in the greater

quantity.

SoluteSolute

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

Hydrophilic MaterialsHydrophilic Materials

Materials that dissolve in water.Hydro - waterphilic - to like or loveHave ionic or polar regions (polar

covalent bonds) on their molecules for H+ bonds.

Materials that dissolve in water.Hydro - waterphilic - to like or loveHave ionic or polar regions (polar

covalent bonds) on their molecules for H+ bonds.

HydrophobicHydrophobic

Materials that repel water.Hydro - waterphobic - to fearHave non-polar covalent bonds. Ex

- lipids.

Materials that repel water.Hydro - waterphobic - to fearHave non-polar covalent bonds. Ex

- lipids.

Solution ConcentrationSolution Concentration

Usually based on Molarity.Molarity - the number of moles of

solute per liter of solution.

Usually based on Molarity.Molarity - the number of moles of

solute per liter of solution.

MolesMoles

The molecular weight of a substance in grams.

One Avogadro’s number of molecules.

6.02 X 1023

The molecular weight of a substance in grams.

One Avogadro’s number of molecules.

6.02 X 1023

One Mole of eachOne Mole of each

Sulfur

Copper Sulfate

Mercury Oxide

Copper

Sodium Chloride

CommentComment

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

Dissociation of WaterDissociation of WaterWater can sometimes split into two

In pure water the concentration of

each ion is 10-7 M

Water can sometimes split into two ions.

In pure water the concentration of

each ion is 10-7 M

Adding certain solutes disrupts the balance between the two ions.

The two ions are very reactive and can drastically affect a cell.

Adding certain solutes disrupts the balance between the two ions.

The two ions are very reactive and can drastically affect a cell.

AcidsAcids

Materials that can release H+

Example: HCl

HCl H+ + Cl-

Materials that can release H+

Example: HCl

HCl H+ + Cl-

Acid RainAcid Rain

BasesBases

Materials that can absorb H+

Often reduce H+ by producing OH-

Example: NaOH

NaOH Na+ + OH-

Materials that can absorb H+

Often reduce H+ by producing OH-

Example: NaOH

NaOH Na+ + OH-

NeutralsNeutrals

Materials that are neither acids nor bases.

pH ScalepH Scale

A logarithmic scale for showing H+ concentration

pH = - log [H+]

A logarithmic scale for showing H+ concentration

pH = - log [H+]

pH ScalepH Scale

Example:Example:

For a neutral solution:[H+] is 10-7

or - log 10-7 or - (-7)or 7

For a neutral solution:[H+] is 10-7

or - log 10-7 or - (-7)or 7

Acids: pH <7 etc.

Bases: pH >7 etc.

Each pH unit is a 10x change in H+

Acids: pH <7 etc.

Bases: pH >7 etc.

Each pH unit is a 10x change in H+

CommentComment

[H+] + [OH-] = 14Therefore, if you know the

concentration of one ion, you can easily calculate the other.

[H+] + [OH-] = 14Therefore, if you know the

concentration of one ion, you can easily calculate the other.

BuffersBuffers

Materials that have both acid and base properties.

Resist pH shifts.Cells and other biological solutions

often contain buffers to prevent damage.

Materials that have both acid and base properties.

Resist pH shifts.Cells and other biological solutions

often contain buffers to prevent damage.

SummarySummary

Be able to discuss the properties of water.

Be able to measure solution concentrations in Molarity.

Be able to work pH scale questions.

Be able to discuss the properties of water.

Be able to measure solution concentrations in Molarity.

Be able to work pH scale questions.

Should we control a chemical that: G Causes excessive sweating and vomiting. G Is a major component...

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