Skip to main content
Back

Water, Hydrogen Ions, and the Chemistry of Life

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Water and Life

Hydrogen Ions and Water Dissociation

Water molecules can undergo dissociation, a process where a hydrogen atom leaves its electron behind and transfers as a proton to another water molecule. This process is fundamental to understanding acids, bases, and pH in biological systems.

  • Hydrogen Ion (H+): A hydrogen atom that has lost its electron, leaving behind a single proton with a positive charge.

  • Hydronium Ion (H3O+): When a water molecule gains a proton (H+), it becomes a hydronium ion.

  • Hydroxide Ion (OH-): The water molecule that loses a proton becomes a hydroxide ion.

Chemical Equation for Water Dissociation:

  • H+ Notation: H+ is often used to represent H3O+, but in reality, free protons do not exist alone in water; they are always associated with water molecules as hydronium ions.

Properties and Rarity of Water Dissociation

The dissociation of water is a rare event, but it is crucial for the chemistry of life.

  • Frequency: A single water molecule dissociates only about once every 554 million molecules at any given time.

  • Effect of Solutes: Adding certain kinds of solutes can disrupt the balance of hydrogen and hydroxide ions, affecting the pH of the solution.

Example: The addition of acids or bases to water will shift the balance of H3O+ and OH- ions, changing the solution's pH.

Handwritten notes on water dissociation and hydrogen ions

Pearson Logo

Study Prep