Chemistry of Water and Acids

Study Notes

Water is a polar molecule, meaning it has a slightly positive charge on the hydrogen atoms and a slightly negative charge on the oxygen atom.
This polarity gives water many of its unique properties and allows it to dissolve a wide variety of substances.
Water is a universal solvent, meaning it can dissolve both ionic and polar compounds.
Water is essential for many biological processes, including cellular metabolism, temperature regulation, and photosynthesis.

An acid is a molecule that donates a proton (H+ ion) in a solution.
Acids are characterized by a pH below 7.
Strong acids completely dissociate in water, releasing all their H+ ions. Examples:
- Hydrochloric acid (HCl)
- Sulfuric acid (H2SO4)
- Nitric acid (HNO3)
Weak acids only partially dissociate in water, releasing some of their H+ ions. Examples:
- Acetic acid (CH3COOH)
- Citric acid (C6H8O7)
Acid strength is measured by the acid dissociation constant (Ka).

A base is a molecule that accepts a proton (H+ ion) in a solution.
Bases are characterized by a pH above 7.
Strong bases completely dissociate in water, releasing all their OH- ions. Examples:
- Sodium hydroxide (NaOH)
- Calcium hydroxide (Ca(OH)2)
Weak bases only partially dissociate in water, releasing some of their OH- ions. Examples:
- Ammonia (NH3)
- Trimethylamine (N(CH3)3)
Base strength is measured by the base dissociation constant (Kb).

The pH scale measures the concentration of H+ ions in a solution.
pH ranges from 0 (very acidic) to 14 (very basic).
A pH of 7 is neutral, meaning the solution has an equal concentration of H+ and OH- ions.
pH is calculated using the formula: pH = -log[H+]

Water is a polar molecule with a slightly positive charge on the hydrogen atoms and a slightly negative charge on the oxygen atom.
Water's polarity allows it to dissolve a wide variety of substances, making it a universal solvent.
Water is essential for many biological processes, including cellular metabolism, temperature regulation, and photosynthesis.

Acids are molecules that donate a proton (H+ ion) in a solution.
Acids have a pH below 7 and can be either strong or weak.
Strong acids completely dissociate in water, releasing all their H+ ions, examples include hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid (HNO3).
Weak acids only partially dissociate in water, releasing some of their H+ ions, examples include acetic acid (CH3COOH) and citric acid (C6H8O7).
Acid strength is measured by the acid dissociation constant (Ka).

Bases are molecules that accept a proton (H+ ion) in a solution.
Bases have a pH above 7 and can be either strong or weak.
Strong bases completely dissociate in water, releasing all their OH- ions, examples include sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2).
Weak bases only partially dissociate in water, releasing some of their OH- ions, examples include ammonia (NH3) and trimethylamine (N(CH3)3).
Base strength is measured by the base dissociation constant (Kb).

The pH scale measures the concentration of H+ ions in a solution.
pH ranges from 0 (very acidic) to 14 (very basic).
A pH of 7 is neutral, meaning the solution has an equal concentration of H+ and OH- ions.
pH is calculated using the formula: pH = -log[H+].