Chemical Equilibrium and the Acidification of the Ocean A Chem 30 Lesson Jordan Sevenhuysen February 9 th, 2012

Chemical Equilibrium Jordan Sevenhuysen The Problem: How does atmospheric CO 2 levels effect the pH of the ocean? What does this mean for marine organisms? Carbon Cycle Learning Tool Carbon Cycle Learning Tool Ocean Acidification GrapherOcean Acidification Grapher

H 2 O + CO 2(aq) H 2 CO 3 HCO 3 – H + + CO 3 2– K a2 = 4.7×10 −11 CaCO 3 Ca 2+ + CO 3 2– Chemical Equilibrium Jordan Sevenhuysen H 2 CO 3 H + + HCO 3 – K a1 = 2.5×10 −4 P(CO 2 ) = k H [CO 2(aq) ] CO 2 and Ocean pH Applet

H 2 O + CO 2(aq) H 2 CO 3 K h = 1.70×10 −3 HCO 3 – H + + CO 3 2– K a2 = 4.7×10 −11 CaCO 3 Ca 2+ + CO 3 2– K sp = 3.7×10 −9 to 8.7×10 −9 Chemical Equilibrium Jordan Sevenhuysen H 2 CO 3 H + + HCO 3 – K a1 = 2.5×10 −4 P(CO 2 ) = k H [CO 2(aq) ] k H = atm/(mol/L)

Concepts Developed/Used: Equilibrium systems Le Chatelier’s Principle ICE tables Acid/Bases K a, K b Main goal is to have students work with and explore equilibrium expressions and equations. Chemical Equilibrium Jordan Sevenhuysen

POS Objectives Unit D: Chemical Equilibrium Focusing on Acid-Base Systems Students will explain that there is a balance of opposing reactions in chemical equilibrium systems. (General Outcome 1) Students will identify, write and interpret chemical equations for systems at equilibrium. (30-D1.2k) Predict, qualitatively, using Le Chatelier’s principle, shifts in equilibrium caused by changes in temperature, pressure, volume, concentration or the addition of a catalyst and describe how these changes affect the equilibrium constant. (30-D1.3k) Chemical Equilibrium Jordan Sevenhuysen