Properties of Water

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Blood & Cytoplasm are suspensions

Slide 12

Acids, Bases & pH

1 water molecule in 550 million naturally dissociates into a Hydrogen Ion and a Hydroxide Ion

Hydrogen Ion Hydroxide Ion

Acid Base

H2O  H+ + OH-

Slide 13

The pH Scale

Indicates the concentration of H+ ions

Ranges from 0 – 14

pH of 7 is neutral

pH 0 up to 7  acid … H+

pH above 7 to 14  base… OH-

Each pH unit represents a factor of 10X change in concentration

How much stronger is a pH3 than a pH of 5?

Slide 14

Acids

Strong Acid = pH 1-3

High in H+ ions

Lower number of OH- ions

Slide 15

Bases

Strong Base = pH 11 – 14

High in OH-ions

Lower in number of H+ ions

Slide 16

Buffers

Weak acids or bases that react with strong acids or bases

Made by the body

Prevent sharp, sudden changes in pH (keep pH neutral)

Weak Acid

Weak Base