properties of water where there is ________, there is __________!
TRANSCRIPT
Properties of Water
Where there is ________, there is __________!
Properties of Water
Where there is life, there is
Water!
I. Chemical Formula
• Organisms are _____% - _____% Water• The 6 most common atoms found in living things
(makes up about 99% of our body) are:1.2.3.4.5.6.
Acronym: _ _ _ _ _ _
I. Chemical Formula
• Organisms are 50% - 90% Water• The 6 most common atoms found in living things
(makes up about 99% of our body) are:1. Sulfur (S)2. Phosphorus (P)3. Oxygen (O)4. Nitrogen (N)5. Carbon (C)6. Hydrogen (H)
Acronym: SPONCH
II. Molecular Structure
O-
H+ H+
Water is a ___________ molecule (Has a ____________ at each end). The specific molecular structure of water leads to the different properties that we will talk about.
II. Molecular Structure
O-
H+ H+
Water is a polar molecule (Has a charge at each end). The specific molecular structure of water leads to the different properties that we will talk about. Note: Water is bent because oxygen has a higher electronegativity, therefore there is an unequal sharing of electrons in oxygen’s favor.
III. Properties of Water
1. Water is an excellent _________. Why?
Water is charged at both ends and can therefore, bond to any ________ molecule.
III. Properties of Water
1. Water is an excellent solvent . Why?
Water is charged at both ends and can therefore, bond to any charged molecule. H+ H+
O-
Salt: NaCl (sodium chloride)• When salt dissolves in water: Na+ separates from Cl- • Where would salt bond to water?
H+ H+---Cl-
Na+---O-
• Why is it biologically critical that water be an excellent solvent?
1. ______________
2. ______________
3. ______________
This diagram shows salt dissolving in water.
H+ H+---Cl-
Na+---O-
• Why is it biologically critical that water be an excellent solvent?
• Bloodstream (our blood is made of 50% water that dissolves/circulates nutrients)
• Waste excreted from our body is carried via water.
• Minerals/Nutrients absorbed by plants via water.
This diagram shows salt dissolving in water.
•Detergents
Detergents are special molecules because they are __________ (charged) on one end and __________ (uncharged) on the other end.
(-)
(No charge)
Example:
Phosopholipid
Sticks to ___________molecules
Sticks to _________molecules
•Detergents
Detergents are special molecules because they are polar (charged) on one end and
nonpolar (uncharged) on the other end.
(-)
(No charge)
Example:
Phosopholipid
Sticks to charged molecules
Sticks to nonpolar molecules.
Soap (detergent)
Polar end ---- H2O (Goes down drain)
Nonpolar end ---- Nonpolar substance(grease/oil)
(Pulled along with water)
• Hydrophobic: (Water-______) does not bond to water – has no charge).
• Hydrophilic: (Water-_______)Has an affinity to water – is charged.
III. Properties of Water (Cont.)
2. Water has Surface Tension: Water forms a ________ at the surface.
• Water has the ability to stick to a second water molecule. Called ___________. Water has a greater attraction to other water molecules than to the molecules in the air.
• Water sticks to another water molecule when a _____ charged hydrogen forms a hydrogen bond with a _______ charged oxygen.
• This type of bond is fairly weak.
III. Properties of Water (Cont.)
2. Water has Surface Tension: Water forms a blanket at the surface.
• Water has the ability to stick to a second water molecule. Called cohesion . Water has a greater attraction to other water molecules than to the molecules in the air.
• Water sticks to another water molecule when a + charged hydrogen forms a hydrogen bond
with a - charged oxygen.• This type of bond is fairly weak.
The Three States of Water
H+ H+---O-
-O--- H+ H+
Biological significance of water having surface tension:
This is a waterstrider that literally “walks on water”
Detergents disrupt surface tension! Why????
Dive Belly flop
VSOuch!
III. Properties of Water (Cont.)
3. Water has a high heat capacity • Holds on to heat well.• Resists temperature change. Why? A lot of ________
must be taken _______ to cool water or a lot of __________ must be put in to ________ water.
III. Properties of Water (Cont.)
3. Water has a high heat capacity • Holds on to heat well.• Resists temperature change. Why? A lot of energy
must be taken out to cool water or a lot of energy must be put in to warm water.
• Biological significance: Oceans maintain steady temps throughout year. Most ocean life cannot regulate body temp.
• Sweating (evaporation) creates a cooling effect!
III. Properties of Water (Cont.)
4. Ice Floats – Water changes density at 4°C• Colder water is more dense (_________) than warmer
water until 4°C. Because of the structure of ice, water molecules begin to spread out again and ice floats.
Lake in fall Lake in spring
(Temp. range: 4°- 7°) (Temp. range: 0°- 4°)
ICE___°C___°C___°C___°C___°C
___°C___°C___°C___°C___°C
III. Properties of Water (Cont.)
4. Ice Floats – Water changes density at 4°C• Colder water is more dense (_________) than warmer
water until 4°C. Because of the structure of ice, water molecules begin to spread out again and ice floats.
Lake in fall Lake in winter
(Temp. range: 4°- 8°) (Temp. range: 0°- 4°)
ICE 8 °C 7 °C 6 °C 5 °C 4 °C
0 °C 1 °C 2 °C 3 °C 4 °C
Biological Significance: Wildlife can survive winter!! Ice acts as an insulator.
• Biological Significance: With the changing of the seasons, this property of Water leads to a thermal overturn:
Melting of Ice:
0°C
4°C
2°C
6°C
Nutrients (phosphates and nitrates) are circulated throughout the lake for living things.
III. Properties of Water (Cont.)
5. Water has adhesive and cohesive properties.
• Water sticks to _________. (Cohesion)• Water sticks to _________ molecules. (Adhesion)
III. Properties of Water (Cont.)
5. Water has adhesive and cohesive properties.
• Water sticks to water . (Cohesion)• Water sticks to charged molecules. (Adhesion)
Water sticks to charged xylem tissue in plants.
Water sticks to water
Biological significance: Water can travel up trees from roots to leaves!