1. Water and Carbon What are the emergent properties of water?
What are the emergent properties of carbon?

2. Figure 3.1
Figure 3.1 How does the habitat of a polar bear depend on the chemistry of water? 2

3. Concept 3.1: Polar covalent bonds in water molecules result in hydrogen bonding
The water molecule is a polar molecule: the opposite ends have opposite charges
Polarity allows water molecules to form hydrogen bonds with each other
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4.   Hydrogen bond  + Polar covalent bonds    +    +    +
Figure 3.2  
Hydrogen
bond  +
Polar covalent
bonds    +    +    +
Figure 3.2 Hydrogen bonds between water molecules. 4

5. Concept 3.2: Four emergent properties of water contribute to Earth’s suitability for life
Four of water’s properties that facilitate an environment for life are
Cohesive/Adhesive behavior
Ability to moderate temperature
Expansion upon freezing
Versatility as a solvent
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6. Cohesion of Water Molecules
Collectively, hydrogen bonds hold water molecules together, a phenomenon called cohesion
Cohesion helps the transport of water against gravity in plants
Adhesion is an attraction between different substances, for example, between water and plant cell walls
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7. Two types of water-conducting cells
Figure 3.3
Adhesion
Two types of
water-conducting
cells
Cohesion
Direction
of water
movement
Figure 3.3 Water transport in plants.
300 m 7

8. Surface tension is related to cohesion
Surface tension is a measure of how hard it is to break the surface of a liquid
Surface tension is related to cohesion
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9. Water’s High Specific Heat
The specific heat of a substance is the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1ºC
The specific heat of water is 1 cal/g/ºC
Water resists changing its temperature because of its high specific heat
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10. Water’s high specific heat can be traced to hydrogen bonding
Heat is absorbed when hydrogen bonds break
Heat is released when hydrogen bonds form
The high specific heat of water minimizes temperature fluctuations to within limits that permit life
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11. Moderation of Temperature by Water
Water absorbs heat from warmer air and releases stored heat to cooler air
Water can absorb or release a large amount of heat with only a slight change in its own temperature
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12. Los Angeles (Airport) 75°
Figure 3.5
San Bernardino
100°
Burbank
90°
Santa Barbara 73°
Riverside 96°
Los Angeles
(Airport) 75°
Santa Ana
84°
Palm Springs
106°
70s (°F)
80s
Pacific Ocean 68°
90s
Figure 3.5 Effect of a large body of water on climate.
100s
San Diego 72°
40 miles 12

13. Evaporative Cooling
Evaporation is transformation of a substance from liquid to gas
Heat of vaporization is the heat a liquid must absorb for 1 g to be converted to gas
As a liquid evaporates, its remaining surface cools, a process called evaporative cooling
Evaporative cooling of water helps stabilize temperatures in organisms and bodies of water
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14. Floating of Ice on Liquid Water
Ice floats in liquid water because hydrogen bonds in ice are more “ordered,” making ice less dense
Water reaches its greatest density at 4°C
If ice sank, all bodies of water would eventually freeze solid, making life impossible on Earth
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15. Hydrogen bond Liquid water: Hydrogen bonds break and re-form Ice:
Figure 3.6
Hydrogen bond
Liquid water:
Hydrogen bonds
break and re-form
Figure 3.6 Ice: crystalline structure and floating barrier.
Ice:
Hydrogen bonds
are stable 15

16. Water: The Solvent of Life
Water is a versatile solvent due to its polarity, which allows it to form hydrogen bonds easily
When an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules called a hydration shell
Water can also dissolve compounds made of nonionic polar molecules
Even large polar molecules such as proteins can dissolve in water if they have ionic and polar regions
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17.                    Na Na Cl Cl Figure 3.7
Figure 3.7 Table salt dissolving in water. 17

18. What are the emergent properties of carbon?
Can form single or double covalent bonds
Can form isomers
Mainly that it is extremely versatile!