How does seawater act as a buffer?

Answer 1

Acetic acid (CH3COOH) is a weak acid, and acetate ion (CH3COO-) is a weak base. Together, acetic acid and acetate ions form a conjugate acid-base pair. In solution, this conjugate acid-base pair act as a buffer solution. When small amounts of acid or base are added, buffer solutions are able to resist changes in pH. The conjugate acid-base pair work to protect the pH of the solution by balancing out the hydrogen ions supplied by the additional acid or balancing out the hydroxide ions supplied by the additional base.

When an acid such as hydrochloric acid (HCl) is added to a buffer solution, only the hydrogen ions from the acid affect the solution. The remaining ions, in this case chlorine ions, are spectator ions; they do not participate in the reaction.

The HCl reacts with the base component of the buffer and produces more of the buffer's acid component. Adding more acid decreases the pH of the solution, if the buffer solution does not remove these new hydrogen ions. The buffer removes the hydrogen ions, and they react with the hydroxide ions of the base. So the pH remains unchanged.

When a base is added to a buffer, the opposite occurs. The base reacts with the acid component of the buffer. This removes the new hydroxide ions and prevents the base from raising the pH.

Answer 2

Because of its solubility and chemical reactivity, CO2 is the most absorbed of all anthropogenic gases. CO2 is dissolved in the ocean and is found in three main forms. 1) Dissolved CO2 (1% of the total) and exchanged with the atmosphere until the partial pressure of the sea surface water and the air are equal. 2) Bicarbonate (91% of the total) 3) Carbonate (8% of the total) As more CO2 is added, the amount of carbonate decreases and the amount of bicarbonate increases. Therefore there is less carbonate available to react with further additions of CO2, causing CO2 to remain in dissolved form. This restricts further uptake so that the ability of the ocean to take up CO2 decreases as the amount of CO2 in the atmosphere increases.

Answer 3

The ocean buffering arises from the fact that the concentration of the various carbon species are much higher than the concentration of the hydrogen ions. The pH of seawater is buffered by the chemistry of carbon, just as is the chemistry of blood and cellular fluids.

Answer 4

Sea water is at the equilibrium:

CO2(aq) +H2O(l) ⇌ HCO3-(aq)+H+(aq)

When an acid is added, there will be more hydrogen ions in the solution, and according to Le Chatelier's principle, this means that the equilibrium will shift to the left, reducing the amount of Hydrogen ions, and therefore keeping the pH (fairly close to) constant.

Answer 5

Seawater acts as a buffer because it contains a combination of dissolved salts which help neutralize changes in pH by absorbing excess hydrogen ions or hydroxide ions. This stabilizes the pH of seawater despite external factors that may try to alter it.

Answer 6

shells ^-^