📚 Topic Summary
The ocean absorbs a significant amount of atmospheric carbon dioxide ($CO_2$). This absorption leads to a series of chemical reactions that alter the ocean's chemistry. When $CO_2$ dissolves in seawater, it forms carbonic acid ($H_2CO_3$), which then dissociates into bicarbonate ($HCO_3^−$) and hydrogen ions ($H^+$). The increase in $H^+$ ions causes ocean acidification, which can have significant impacts on marine life, particularly shellfish and coral reefs. Understanding these processes is crucial for predicting the long-term effects of climate change.
The process can be summarized by the following equations:
$CO_2 (g) \rightleftharpoons CO_2 (aq)$ (Dissolution of carbon dioxide)
$CO_2 (aq) + H_2O (l) \rightleftharpoons H_2CO_3 (aq)$ (Formation of carbonic acid)
$H_2CO_3 (aq) \rightleftharpoons H^+ (aq) + HCO_3^- (aq)$ (Dissociation into bicarbonate)
$HCO_3^- (aq) \rightleftharpoons H^+ (aq) + CO_3^{2-} (aq)$ (Dissociation into carbonate)
🧪 Part A: Vocabulary
Match the terms with their definitions:
| Term |
Definition |
| 1. Ocean Acidification |
A. The process where $CO_2$ dissolves in seawater. |
| 2. Carbonic Acid |
B. An ion with the formula $HCO_3^-$. |
| 3. Bicarbonate |
C. The reduction in pH of the ocean due to increased $CO_2$ absorption. |
| 4. Dissolution |
D. A weak acid formed when $CO_2$ reacts with water ($H_2CO_3$). |
| 5. Carbonate Ion |
E. An ion with the formula $CO_3^{2-}$. |
Match the term to the correct definition. For example: 1-C
💧 Part B: Fill in the Blanks
Fill in the blanks with the correct words from the list: carbon dioxide, pH, carbonic acid, bicarbonate, hydrogen ions.
When __________ dissolves in seawater, it forms __________. This acid dissociates into __________ and __________. The increase in __________ causes a decrease in the ocean's __________, leading to ocean acidification.
🤔 Part C: Critical Thinking
Explain how increased ocean acidification can impact marine ecosystems and what steps can be taken to mitigate these effects.