2006-11-30 21:20:21 · 3 answers · asked by sweetgurl_16 1 in Science & Mathematics ➔ Chemistry
When in an acid+salt buffer the temperature increases more acid can dissociate forming more H+. The pH therefore decreases.
In an base+salt buffer the same reasoning holds for the OH- ions and the pH increases.
2006-12-01 00:14:53 · answer #1 · answered by cordefr 7 · 0⤊ 1⤋
In the buffers you have equilibria including that of the self dissociation of water. Therefore the effect of temperature will depend on the effect on all equilibria.
It is not at all easy to foresee the change.
E.g. for Tris-HCl which is a weak base buffer, you have
dpH/dθ= -0.028 meaning that the pH DROPS by 0.028 units for an increase of 1 Celsius.
There are tables with such values. For some buffers dpH/dθ is positive, for others negative but the sign has nothing to do with whether it is a buffer of a weak base or a weak acid.
2006-12-01 02:53:40 · answer #2 · answered by bellerophon 6 · 0⤊ 0⤋
Shofix provides a very reliable link (the 0.33 one). "dpH(S)/dT popular replace of pH fee according to degree centigrade. it quite is helpful or destructive" reckoning on the reactions in touch (endothermic or exothermic) there will be a cut back or develop of pH with an develop of temperature. as an instance for Tris-HCl you have dpH/dT=-0.028 pH instruments/ degC, whilst for Tetraoxolate +0.070
2016-12-14 10:17:35 · answer #3 · answered by ? 4 · 0⤊ 0⤋