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Chemistry vocabulary · Acids, Bases and Salts

Buffer

Meaning in chemistry, with examples

/ˈbʌfə/nounCommon term

In chemistry, buffer means: A solution that resists changes in pH when small amounts of acid or base are added. It usually contains a weak acid and its conjugate base, such as acetic acid and sodium acetate.

In Turkish: tampon çözelti, tampon

How it is used

Essential in biochemistry, analysis and instrument calibration. You prepare or make up a buffer and adjust its pH; people speak of 'a phosphate buffer at pH 7.4' and of buffer capacity. pH meters are calibrated with standard buffers.

Example sentences

  1. Calibrate the pH meter with the pH 4 and pH 7 buffers.

  2. Blood is a natural buffer system that keeps the pH near 7.4.

Common collocations

  • buffer solution
  • phosphate buffer
  • prepare a buffer
  • buffer capacity
  • buffer pH
  • pHA scale, usually from 0 to 14, that shows how acidic or basic a solution is. Below 7 is acidic, 7 is neutral at 25 °C and above 7 is basic; it equals −log[H⁺].
  • acidA substance that releases hydrogen ions (H⁺) in water or, more generally, donates protons. Its water solutions have a pH below 7 and turn blue litmus paper red.
  • baseA substance that accepts protons (H⁺) or releases hydroxide ions (OH⁻) in water. Its solutions have a pH above 7 and turn red litmus paper blue.
  • indicatorA substance that changes color at a certain pH or at the end of a reaction, used to show when a titration is complete. Phenolphthalein and methyl orange are common examples.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Acids, Bases and Salts

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