Skip to ContentGo to accessibility page
OpenStax Logo
Chemistry: Atoms First

Key Terms

Chemistry: Atoms FirstKey Terms

Key Terms

acid ionization
reaction involving the transfer of a proton from an acid to water, yielding hydronium ions and the conjugate base of the acid
acid ionization constant (Ka)
equilibrium constant for the ionization of a weak acid
acid-base indicator
organic acid or base whose color changes depending on the pH of the solution it is in
acidic
describes a solution in which [H3O+] > [OH−]
amphiprotic
species that may either gain or lose a proton in a reaction
amphoteric
species that can act as either an acid or a base
autoionization
reaction between identical species yielding ionic products; for water, this reaction involves transfer of protons to yield hydronium and hydroxide ions
base ionization
reaction involving the transfer of a proton from water to a base, yielding hydroxide ions and the conjugate acid of the base
base ionization constant (Kb)
equilibrium constant for the ionization of a weak base
basic
describes a solution in which [H3O+] < [OH−]
Brønsted-Lowry acid
proton donor
Brønsted-Lowry base
proton acceptor
buffer
mixture of a weak acid or a weak base and the salt of its conjugate; the pH of a buffer resists change when small amounts of acid or base are added
buffer capacity
amount of an acid or base that can be added to a volume of a buffer solution before its pH changes significantly (usually by one pH unit)
color-change interval
range in pH over which the color change of an indicator takes place
conjugate acid
substance formed when a base gains a proton
conjugate base
substance formed when an acid loses a proton
diprotic acid
acid containing two ionizable hydrogen atoms per molecule. A diprotic acid ionizes in two steps
diprotic base
base capable of accepting two protons. The protons are accepted in two steps
Henderson-Hasselbalch equation
equation used to calculate the pH of buffer solutions
ion-product constant for water (Kw)
equilibrium constant for the autoionization of water
leveling effect of water
any acid stronger than H3O+,H3O+, or any base stronger than OH− will react with water to form H3O+,H3O+, or OH−, respectively; water acts as a base to make all strong acids appear equally strong, and it acts as an acid to make all strong bases appear equally strong
monoprotic acid
acid containing one ionizable hydrogen atom per molecule
neutral
describes a solution in which [H3O+] = [OH−]
oxyacid
compound containing a nonmetal and one or more hydroxyl groups
percent ionization
ratio of the concentration of the ionized acid to the initial acid concentration, times 100
pH
logarithmic measure of the concentration of hydronium ions in a solution
pOH
logarithmic measure of the concentration of hydroxide ions in a solution
stepwise ionization
process in which an acid is ionized by losing protons sequentially
titration curve
plot of the pH of a solution of acid or base versus the volume of base or acid added during a titration
triprotic acid
acid that contains three ionizable hydrogen atoms per molecule; ionization of triprotic acids occurs in three steps
PreviousNext
Order a print copy
Citation/Attribution
Reuse and redistribution of this content in digital or print format:
  • This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's prior written permission.
  • This book uses the Creative Commons Attribution License, which means that you can reuse and modify the material only for noncommercial purposes, must attribute OpenStax, and must distribute any derivative works under the same license.
  • Any commercial printing of this textbook, including using a local or custom printer, must be approved by OpenStax, and proper citation provided.
  • OpenStax-copyrighted images, activities, assessments, and similar components of this book are subject to the same licensing – CC-BY-NC-SA. They can be used for noncommercial purposes with attribution. Commercial use requires permission.
  • Permission requests: Anyone who intends to incorporate this content (including text, images, and other components) into large language models, use it in AI offerings, use it commercially (including in print), and/or has questions about another use case is welcome to complete our reuse request form.
Attribution information
  • If you are redistributing all or part of this book in a noncommercial print format, then you must include on every physical page the following attribution:

    Access for free at https://openstax.org/books/chemistry-atoms-first/pages/1-introduction

  • If you are redistributing all or part of this book in a noncommercial digital format, then for every page that includes OpenStax content, you must license the derivative work under the same CC-BY-NC-SA license as the original, and include on every digital page view the following attribution:

    Access for free at https://openstax.org/books/chemistry-atoms-first/pages/1-introduction

Citation information

The information below includes the information needed to generate citations in most major styles (APA, MLA, etc.); you must reformat and organize the information as needed to fit the requirements of the style. Use the information below to generate a citation. We recommend using a citation tool such as this one.

© Feb 15, 2022 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License. The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo, and Rice University name, and Rice University logo trademarks, or wordmarks are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.