buffer

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A solution that resists change in pH when small amounts of an acid or alkali are added over a certain range or when the solution is diluted. Acidic buffers consist of a weak acid with a salt of the acid. The salt provides the negative ion A⁻, which is the conjugate base of the acid HA. An example is carbonic acid and sodium hydrogencarbonate. Basic buffers have a weak base and a salt of the base (to provide the conjugate acid). An example is ammonia solution with ammonium chloride.

In an acidic buffer, for example, molecules HA and ions A⁻ are present. When acid is added most of the extra protons are removed by the base:

When base is added, most of the extra hydroxide ions are removed by reaction with undissociated acid:
Thus, the addition of acid or base changes the pH very little. The hydrogen-ion concentration in a buffer is given by the expression
i.e. it depends on the ratio of conjugate base to acid. As this is not altered by dilution, the hydrogen-ion concentration for a buffer does not change much during dilution.

In the laboratory, buffers are used to prepare solutions of known stable pH. Natural buffers occur in living organisms, where the biochemical reactions are very sensitive to change in pH. The main natural buffers are H₂CO₃/HCO₃ ⁻ and H₂PO₄ ⁻/HPO₄ ²⁻. Buffer solutions are also used in medicine (e.g. in intravenous injections), in agriculture, and in many industrial processes (e.g. dyeing, fermentation processes, and the food industry).

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noun
noun, Brit

A silly or incompetent old man; often in phr. old buffer. (1749 —) .
London Review of Books I take my stand beside the other old buffers here (1979).

[Prob. from obs. buff verb, imitative of the sound of a soft body being struck, or from obs. buff verb, to stutter.]

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1. any substance or mixture of substances that, when dissolved (usually in water), will maintain its solution at approximately constant pH despite small additions of acid or base. The commonest examples are moderately strong solutions containing both a weak acid and its conjugate base (or a weak base and its conjugate acid). A substance is useful as a buffer over a range of about one pH unit either side of its pK, but is most effective at or near the pK. Buffer substances used for biochemical or biological purposes include: acetate, bicarbonate, bis-tris propane, borate, citrate, dimethylmalonate, glycinamide, glycylglycine, imidazole, phosphate, succinate, and Tris together with any good buffer substances. By extension, the term may be applied to agents controlling the activities of various other specified entities, e.g. redox buffer, carbon-dioxide buffer, metal-ion buffer. Also used attributively: e.g. buffer action; buffer salt; buffer solution.
2. a solution of a buffer (def. 1).
3. a short-term storage facility (e.g. as part of the memory of a computer), especially one whose patterns or rates of input and output can differ.
4. to treat with or to incorporate a buffer (def. 1); to act as a buffer. See also buffering capacity, buffer value.

—buffered adj.; buffering n.

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The action produced by a buffer.

• b. agents — amongst other uses these substances play a part in dairy cattle nutrition by helping to prevent damaging ruminal acidity on high grain rations. Sodium bicarbonate and magnesium oxide are the preparations most commonly used.

For a list of words related to buffer, see:

• Substances, Particles, and Atomic Architecture - buffer: substance that minimizes changes in pH of a solution by neutralizing added amounts of acid or base
• Machinery and Mechanical Devices - buffer: padding device or cushion used to lessen or absorb shock
• Shaving, Shaping, Sharpening, and Smoothing Tools - buffer: any of various polishing devices, usu. with smoothing surface attached to handle or other mechanism
• Hardware and Peripherals - buffer: intermediate, temporary storage device for holding data until computer or peripheral such as printer is ready to process it
• Memory and Data Storage - buffer: temporary storage area for input, as data to be printed

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See words rhyming with "buffer."

  See crossword solutions for the clue Buffer.

Dansk (Danish)
1.
n. - stødpude, buffer
v. tr. - være stødpude for, være buffer for

idioms:

• buffer state    stødpudestat
• buffer zone    bufferzone, stødpudezone

2.
n. - poleringsklud

3.
n. - støder, gammel støder

Nederlands (Dutch)
buffer, stootkussen, buffergeheugen (computer), oude dwaas, als buffer optreden voor, bufferen (computer), van buffer voorzien

Français (French)
1.
n. - (lit, fig) tampon, (Rail) tampon, butoir, (US, Aut) pare-chocs, (Comput) mémoire-tampon
v. tr. - (Chim) tamponner, (fig) amortir

idioms:

• buffer state    (Pol) état tampon
• buffer zone    zone tampon

2.
n. - peau de chamois, polissoir, polisseur

3.
n. - (GB) vieux fossile (fam)

Deutsch (German)
1.
n. - Puffer, Stoßdämpfer, Prellbock, (EDV) Pufferspeicher, (electr.) Trennkreis, Rücklage
v. - abdampfen, als Puffer wirken

idioms:

• buffer state    Pufferstaat
• buffer zone    Pufferzone

2.
n. - Polierer, Poliermaschine

3.
n. - (ugs) alter Zausel

Ελληνική (Greek)
n. - (μηχαν.) αποσβεστήρας, αμορτισέρ, αποκρουστήρας βαγονιού, (Η/Υ) ενδιάμεση μνήμη (για προσωρινή αποθήκευση δεδομένων)

idioms:

• buffer state    παρεμβαλλόμενο ουδέτερο κράτος
• buffer zone    ουδέτερη ζώνη

Italiano (Italian)
respingente, riserva

idioms:

• buffer state    stato cuscinetto
• buffer zone    zona cuscinetto

Português (Portuguese)
n. - pára-choque (m), protetor (m), velhinho (m) (gír.)

idioms:

• buffer state    estado (m) tampão (Quím.)
• buffer zone    zona (f) neutra separando grupos ou forças opostas

Русский (Russian)
буфер, амортизатор, демпфер

idioms:

• buffer state    буферное государство
• buffer zone    буферная зона

Español (Spanish)
1.
n. - tope, parachoques, amortiguador, memoria intermedia
v. tr. - amortiguar

idioms:

• buffer state    estado tapón
• buffer zone    zona intermedia

2.
n. - franela

3.
n. - persona anticuada o retrógrada

Svenska (Swedish)
n. - buffert

中文（简体）(Chinese (Simplified))
1. 缓冲存储器, 作用的人

idioms:

• buffer state    缓冲国
• buffer zone    缓冲地带, 中立地区

2. 缓冲器, 减震器, 起缓冲作用的人, 缓冲

中文（繁體）(Chinese (Traditional))
1.
n. - 緩衝記憶體, 作用的人

idioms:

• buffer state    緩衝國
• buffer zone    緩衝地帶, 中立地區

2.
n. - 緩衝器, 減震器, 起緩衝作用的人
v. tr. - 緩衝

한국어 (Korean)
1.
n. - 완충장치[물, 제]
v. tr. - ~을 완충하다

2.
n. - 윤 내는 사람[기구]

3.
n. - 구식 사내

日本語 (Japanese)
n. - 緩衝器, 緩和するもの, 緩衝剤, ばかなやつ
v. - 衝撃を和らげる

idioms:

• buffer state    緩衝国
• buffer zone    緩衝地帯

العربيه (Arabic)
‏(الاسم) مصد, مخفف وقع الصدمه‏

עברית (Hebrew)
n. - ‮מנחת, מחליש הלם, סופג זעזוע, פגוש של קרון רכבת או בקצה המסילה, זיכרון זמני לנתונים העוברים בין יחידות-מחשב הפועלות במהירויות שונות‬
v. tr. - ‮חצץ בין‬
n. - ‮מכשיר ליטוש, אדם העובד בליטוש‬
n. - ‮זקן מיושן בהליכותיו‬

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