Chapter 1 Water Essays

1335 Words Aug 9th, 2013 6 Pages
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MOLECULES OF LIFE

1.0 Molecules Of Life
1.1 Water 1.2 Carbohydrates 1.3 Lipids 1.4 Proteins 1.5 Nucleic Acids

1.0 Molecules Of Life
1.1 Water 1.2 Carbohydrates 1.3 Lipids 1.4 Proteins 1.5 Nucleic Acids

Learning Outcomes : (a) Explain the structure of water molecule

Structure: one oxygen atom and two hydrogen atoms :.(H2O) H & O joined together by sharing electrons ~ covalent bond

Learning Outcomes : (a) Explain the structure of water molecule

atoms arrangement ~ form a triangle ~ V-shape (not a straight line) ~ bond angle 104.5° O H H

Learning Outcomes : (a) Explain the structure of water molecule

slightly negative charged on the O atom ~ partially negative (δ-) slightly positive charged on both H atoms ~ partially positive
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High latent heat of vaporization
It takes a lot of body heat to vaporize sweat ~ gives cooling effect because the sweat absorb a lot of heat energy from our bodies Transpiration ~ the vaporization process needs a lot of energy~ cause cooling effect to leaves. helps prevent overheating

Learning Outcomes : (b) Describe the properties of water and its importance

5. Maximum density at 4 oC
As water cools, the molecules come closer together -reaching their maximum density at 4ºC As water freezes/solidifies at 0°C the ice formed is less dense than the cold water around it - because the H bonds in ice space the water molecules far apart

Learning Outcomes : (b) Describe the properties of water and its importance

5. Maximum density at 4 oC

Learning Outcomes : (b) Describe the properties of water and its importance

5. Maximum density at 4 oC ice floats on the cool water below - the floating layer of ice insulates the water below, preventing it from freezing - allowing aquatic life to exist under the frozen surface

Learning Outcomes : (b) Describe the properties of water and its importance

6. High surface tension : cohesive and adhesive forces
H bonds make water molecules stick to each other (cohesion) Water

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