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: 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+ 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+ 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 oxygens 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 ---- H 2 O (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 VS Ouch!

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 fallLake in spring (Temp. range: 4°- 7°) (Temp. range: 0°- 4°) ICE ___°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 fallLake 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!