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WaterWater
Earth the Water PlanetEarth the Water Planet
Earth the Water PlanetEarth the Water Planet
Special Properties of WaterSpecial Properties of Water Universal Solvent Transparency Three Physical Phases Density and Temperature High Specific Heat High Heat of Vaporization Low Compressibility “Stickiness” of Water Molecules Viscosity
Universal Solvent Transparency Three Physical Phases Density and Temperature High Specific Heat High Heat of Vaporization Low Compressibility “Stickiness” of Water Molecules Viscosity
Polarity of Water MoleculesPolarity of Water Molecules
Hydrogen Bonding Between Water Molecules
Hydrogen Bonding Between Water Molecules
Hydrogen Bonding Between Different Molecules
Hydrogen Bonding Between Different Molecules
Universal SolventUniversal Solvent
Solution = A liquid in which two or more substances are homogeneously mixed.
Solvent = Fluid portion of a solution into which other substances are dissolved.
Solute = A substance that is dissolved into a solvent to produce a solution.
Solution = A liquid in which two or more substances are homogeneously mixed.
Solvent = Fluid portion of a solution into which other substances are dissolved.
Solute = A substance that is dissolved into a solvent to produce a solution.
Universal SolventUniversal Solvent
NaCl (sodium chloride)Dissolving Into Water
NaCl (sodium chloride)Dissolving Into Water
Universal SolventUniversal Solvent
Universal SolventUniversal SolventNaCl Dissolving Into WaterNaCl Dissolving Into Water
Universal SolventUniversal SolventNaCl Dissolving Into WaterNaCl Dissolving Into Water
Protein Dissolving Into WaterProtein Dissolving Into Water
Universal SolventUniversal Solvent
Solubility of SolidsSolubility of Solids
In general, the solubility of solids increases with increases in temperature.
In general, the solubility of solids increases with increases in temperature.
Solubility of GasesSolubility of Gases
In general, the solubility of gases decrease with increases in temperature.
In general, the solubility of gases decrease with increases in temperature.
Importance to Living ThingsImportance to Living Things
Water is the solvent in which most of the chemistry of life takes place.
Water is the solvent in which most of the chemistry of life takes place.
TransparencyTransparency
Electromagnetic RadiationElectromagnetic Radiation
Electromagnetic RadiationElectromagnetic Radiation
Light Intensity and Depth in the Ocean
Light Intensity and Depth in the Ocean
Spectral Characteristics of Light with Depth
Spectral Characteristics of Light with Depth
Aquatic plants are able to live and photosynthesize beneath the surface of the water.
Animals are able to see below the surface of the water.
Changing spectral distribution of light with depth influences physiology and behavior of living things.
Aquatic plants are able to live and photosynthesize beneath the surface of the water.
Animals are able to see below the surface of the water.
Changing spectral distribution of light with depth influences physiology and behavior of living things.
Importance to Living ThingsImportance to Living Things
Three Phases of WaterThree Phases of Water
liquidliquid gasgas
solidsolid
Three Phases of WaterThree Phases of Water
liquidliquid gasgassolidsolid
Ice vs Liquid WaterIce vs Liquid Water
liquidliquidiceicehydrogen bondshydrogen bonds
Melting and Boiling Temperatures of Water
Melting and Boiling Temperatures of Water
Colligative PropertiesColligative Properties
Dissolved solids increase the boiling point and decrease the freezing point.
Dissolved solids increase the boiling point and decrease the freezing point.
Water exists in all three phases at temperatures found on Earth.
If water behaved like substances with similar molecular weight, water would exist only as a gas and it’s likely that the Earth’s gravity wouldn’t retain water.
Water exists in all three phases at temperatures found on Earth.
If water behaved like substances with similar molecular weight, water would exist only as a gas and it’s likely that the Earth’s gravity wouldn’t retain water.
Importance to Living ThingsImportance to Living Things
Density and TemperatureDensity and Temperature
Above 4°C the density of liquid water decreases as the temperature increases.
As the temperature is decreased from 4°C to 0°C, the density decreases.
Water exhibits a density maximum of 1.0 grams/milliliter (g/mL) at 4°C.
Ice is less dense than water.
Above 4°C the density of liquid water decreases as the temperature increases.
As the temperature is decreased from 4°C to 0°C, the density decreases.
Water exhibits a density maximum of 1.0 grams/milliliter (g/mL) at 4°C.
Ice is less dense than water.
Density Behavior of WaterDensity Behavior of Water
Specific GravitySpecific Gravity
Ice floats on top of liquid water. If ice were more dense than liquid
water, then ice would sink, leading to a freezing-over of many lakes and streams.
Ice floats on top of liquid water. If ice were more dense than liquid
water, then ice would sink, leading to a freezing-over of many lakes and streams.
Importance to Living ThingsImportance to Living Things
Ice Floats!Ice Floats!
High Specific HeatHigh Specific Heat
1.0 calories of absorbed heat energy will raise the temperature of 1.0 gram of water by 1.0°C.
1.0 calories of absorbed heat energy will raise the temperature of 1.0 gram of water by 1.0°C.
Water can buffer the environment and living things against extreme changes in temperature.
Water can buffer the environment and living things against extreme changes in temperature.
Importance to Living ThingsImportance to Living Things
High Heat of VaporizationHigh Heat of Vaporization At 25°C, 1.0 gram of water must
absorb 580 calories of heat energy in order to be converted from a liquid to a gas.
At 25°C, 1.0 gram of water must absorb 580 calories of heat energy in order to be converted from a liquid to a gas.
Water vapor in the atmosphere moderates the Earth’s climate.
Living things may moderate their body temperatures via evaporation of water from their surfaces (evaporative cooling).
Water vapor in the atmosphere moderates the Earth’s climate.
Living things may moderate their body temperatures via evaporation of water from their surfaces (evaporative cooling).
Importance to Living ThingsImportance to Living Things
Low CompressibilityLow Compressibility
Liquid water does not compress significantly into a smaller volume.
Liquid water does not compress significantly into a smaller volume.
Water can provide shape and form to a living thing (hydrostatic skeleton). For some organisms a hydrostatic skeleton may facilitate movement.
Aquatic organisms may swim.
Water can provide shape and form to a living thing (hydrostatic skeleton). For some organisms a hydrostatic skeleton may facilitate movement.
Aquatic organisms may swim.
Importance to Living ThingsImportance to Living Things
Low CompressibilityLow Compressibility
“Stickiness” of Water Molecules
“Stickiness” of Water Molecules
Cohesion
Adhesion
Surface Tension
Cohesion
Adhesion
Surface Tension
CohesionCohesion The binding together of like
molecules; the binding together of water molecules to each other via hydrogen bonds.
The binding together of like molecules; the binding together of water molecules to each other via hydrogen bonds.
AdhesionAdhesion The binding together of different
molecules; the binding of water molecules to other substances via hydrogen bonds.
The binding together of different molecules; the binding of water molecules to other substances via hydrogen bonds.
Cohesion + AdhesionCohesion + Adhesion
Capillarity Capillarity
Cohesion and Adhesion in Water Transport in a Plant
Cohesion and Adhesion in Water Transport in a Plant
Importance to Living ThingsImportance to Living Things
Surface TensionSurface Tension
Importance to Living ThingsImportance to Living Things
Resistance of a Fluid to Flow
Resistance of a Fluid to Flow
ViscosityViscosity
Colloids and SuspensionsColloids and Suspensions
The viscosity of water may be a significant force resisting movement in very tiny aquatic organisms.
The viscosity of water retards the rate at which small suspended particles may settle through it.
The viscosity of water may influence transport of fluids throughout an organism.
The viscosity of water may be a significant force resisting movement in very tiny aquatic organisms.
The viscosity of water retards the rate at which small suspended particles may settle through it.
The viscosity of water may influence transport of fluids throughout an organism.
Importance to Living ThingsImportance to Living Things
Decomposition of WaterDecomposition of Water
H2O H+ + OH-H2O H+ + OH-
1 in 107 water molecules will decompose this way in a container of pure water ( [H+] = 10-7 M).
Note that the concentration of H+ is equal to the concentration of OH-)
1 in 107 water molecules will decompose this way in a container of pure water ( [H+] = 10-7 M).
Note that the concentration of H+ is equal to the concentration of OH-)
Definition of pHDefinition of pH
pH = -log[H+]pH = -log[H+]
pH of pure water = -log[10-7] = 7pH of pure water = -log[10-7] = 7
AcidsAcids
HCl H+ + Cl-HCl H+ + Cl-
Add excess H+ to the solution such that [H+] > [OH-].
Add excess H+ to the solution such that [H+] > [OH-].
BasesBases
NaOH Na+ + OH-NaOH Na+ + OH-
Remove H+ from the solution such that [H+] < [OH-].
Remove H+ from the solution such that [H+] < [OH-].
pH ScalepH Scale
Neutral 7Acidic <7Basic (alkaline) >7
Neutral 7Acidic <7Basic (alkaline) >7
Type of SolutionType of Solution pH ValuepH Value
pH ScalepH Scale
BuffersBuffers
Chemicals that minimize changes in the pH of a solution.
Chemicals that minimize changes in the pH of a solution.
Enzymes (enzymes regulate chemical pathways in cells and tissues) and other proteins of living things are pH-sensitive.
The pH of physiological solutions may influence chemical equilibria.
Enzymes (enzymes regulate chemical pathways in cells and tissues) and other proteins of living things are pH-sensitive.
The pH of physiological solutions may influence chemical equilibria.
Importance to Living ThingsImportance to Living Things
