Chapter 3 Water Specific heat of Water heat

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Chapter 3 Water

Chapter 3 Water

Specific heat of Water • heat = total amount of KE in molecular movement.

Specific heat of Water • heat = total amount of KE in molecular movement. • temperature = measures the intensity of heat due to the average KE of the molecules. • Specific heat = the amount of heat that must be lost or gained to raise a 1 g substance 1 o. C.

 • Waters’ high specific heat causes it to change temperature less when it

• Waters’ high specific heat causes it to change temperature less when it absorbs or loses a given amount of heat. • Waters’ specific heat tends to stabilize the ocean temperature creating a favorable environment.

Heat of Vaporization • heat of vaporization = quantity of heat a liquid must

Heat of Vaporization • heat of vaporization = quantity of heat a liquid must absorb for 1 g to be converted from liquid to gas. • high heat of vaporization causes evaporative cooling helping to maintain

States of water • Ice is less dense than liquid (10% at 4 o.

States of water • Ice is less dense than liquid (10% at 4 o. C), due to hydrogen bonding. • The characteristic of ice being less dense than liquid provides continued life for aquatic habitats year round.

Solid liquid Gas

Solid liquid Gas

Salt dissolved in water HYDRATION SHELL

Salt dissolved in water HYDRATION SHELL

Dissociation of water • This is a reversible reaction that will reach a state

Dissociation of water • This is a reversible reaction that will reach a state of dynamic equilibrium where the concentration of water exceeds the concentration of the products. • The concentration of each ion in pure water is [10 -7]M (25 o. C). • Although dissociation is rare, changes in the concentration of these reactive molecules can have drastic affects on a cell proteins and molecules.

p. H • In any aqueous solution [H+][OH-] = 10 -14 Molar concentration Therefore

p. H • In any aqueous solution [H+][OH-] = 10 -14 Molar concentration Therefore [H+] = 10 -7 M and [OH-] = 10 -7 M If enough acid is added to increase [H+] = 10 -5 M then [OH-] = 10 -9 M

 • The p. H scale compresses the range of H+ and OH- by

• The p. H scale compresses the range of H+ and OH- by employing logarithms. • The p. H scale is defined as the negative logarithm (base 10) of the H+ concentration p. H = -log [H+] **In a neutral solution -log 10 -7 = -(-7) = 7 ***Each p. H unit represents a 10 x difference in H+ / OH- concentrations!!!!!!

Buffers • Buffers minimize changes in the concentration of H+/OH- in a solution. •

Buffers • Buffers minimize changes in the concentration of H+/OH- in a solution. • Buffers accept H+ from the solution when in access and donate to solution when depleted ie. H 2 CO 3 HCO 3 - + H+ acid H+ acceptor

Dissociation of water

Dissociation of water