Connecting Equilibrium to Ocean Acidification

Learning Resources

Describe how reaction systems shift in response to changes in the surrounding environment, according to changes in Q and K.
Discuss the concept of speciation and how changes to the surrounding environment influence speciation.
Recognize the connection between ocean acidification and the concept of equilibrium through the example of carbonic acid/bicarbonate/carbonate equilibria.

Key ideas 1-4 will equip students with the proper background knowledge, and key ideas 5 and 6 will go further in depth into the connection of equilibrium and ocean acidification.
This lesson includes: multiple definitions of acids and bases, mono/di/polyprotic acids, conjugate acid/base pairs, equilibrium, equilibrium constant, reaction quotient, ionization, acidic/basic/neutral solutions, pH/pOH scale, Le Chatelier’s principle, strong/weak acids and bases, speciation, speciation plots, and ocean acidification.
Incorporate the material in this unit into lesson plans and work through embedded examples. (There are worked examples and “your turn” examples which the students can attempt on their own. Both have detailed answers available)

This visualization models the relationship between atmospheric CO₂ and average ocean pH.
To demonstrate to students, change the position of the CO₂ slider and see what happens to the pH of the ocean. As students will see, as CO₂ levels increase, the pH of the ocean decreases. If you select “show graph”, the speciation graph of carbonate appears. You can also click the pH vs CO₂ option to show another visual of the decrease in pH that accompanies an increase in CO₂ concentration.
In the VC3chem unit on Acids and Bases (Key idea 5) there are questions to use with this learning tool.

This short lesson provides a clear visual representation of the carbon dioxide, carbonate, bicarbonate, and carbonic acid equilibrium. The resource helps directly explain why increased atmospheric CO₂ levels threatens marine organisms.