pH and Living Things

Ionization of Water H2O H+ + OH- Pure water will ionize (become ions) in the following way to create hydrogen, and hydroxide ions. because of this, water has a neutral pH H2O H+ + OH- water hydrogen ion hydroxide

pH a system to measure the concentration of H+ ions in a solution values range normally from 0-14 Neutral H+ = OH– pH values = 7 pure (distilled) water, salts (NaCl)

pH a system to measure the concentration of H+ ions in a solution values range normally from 0-14 Acids H+ > OH– pH values < 7 lower number = more acidic = more H+

pH a system to measure the concentration of H+ ions in a solution values range normally from 0-14 Bases H+ < OH– pH values > 7 higher number = more basic = more OH–

Water & Solutions

Water & Solutions

Buffers weak acids or bases that prevent big changes in pH in organisms

Human Blood Buffing Example bicarbonate (HCO3–) is used to keep the pH of your blood at 7.4 pH will range from 7.35-7.45 if blood gets too acidic, bicarbonate removes hydrogen ions HCO3– + H+  H2CO3 if blood gets too basic, bicarbonate adds hydrogen ions to hydroxide to make water HCO3– + OH–  CO3–2 + H2O

What property of life is than an example of?!?! HOMEOSTASIS

pH Scale each number represents a change in a factor of 10 on the pH scale a solution with a pH of 5 has 10 times as many hydrogen ions (H+) as one with a pH of 6 pH 5 is 10 times more acidic than pH 6 a solution with a pH of 10 has 10 times as many hydroxide ions (OH–) as one with a pH of 9 pH 10 is 10 times more basic than pH 9

Example 1 How much more acidic is a solution with a pH of 2 than one with a pH of 5? 2 3 4 5 V V V 10 x 10 x 10 pH 2 is 1,000 times more acidic

Example 2 How much more acidic is a solution with a pH of 4 than one with a pH of 6? 4 5 6 V V 10 x 10 pH 4 is 100 times more acidic

Example 3 How much more basic is a solution with a pH of 12 than one with a pH of 8? 8 9 10 11 12 V V V V 10 x 10 x 10 x 10 pH 12 is 10,000 times more basic