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pKa values for acetic, chloroacetic, dichloroacetic and trichloroacetic acids. Inductive effects and mesomeric effects affect the pK a values. A simple example is provided by the effect of replacing the hydrogen atoms in acetic acid by the more electronegative chlorine atom.
When the acidic medium in question is a dilute aqueous solution, the is approximately equal to the pH value, which is a negative logarithm of the concentration of aqueous + in solution. The pH of a simple solution of an acid in water is determined by both K a {\displaystyle K_{{\ce {a}}}} and the acid concentration.
With pOH obtained from the pOH formula given above, the pH of the base can then be calculated from =, where pK w = 14.00. A weak base persists in chemical equilibrium in much the same way as a weak acid does, with a base dissociation constant (K b) indicating the strength of the base. For example, when ammonia is put in water, the following ...
Like all anion exchangers, the resin carries a positive charge that interacts favorably with negative charges. The positive charge of DEAE cellulose is due to a protonated amine group. To ensure that the resin is protonated and positively charged, the chromatography should be performed at least 2 pH units below the pKa of the amine group, 10.
The negative charges create a repulsion that causes the polymer to swell. This swelling behavior is observed when the pH is greater than the pKa of the polymer. [ 2 ] Examples include polymethyl methacrylate polymers (pharmacologyonline 1 (2011)152-164) and cellulose acetate phthalate.
In cell biology, protein kinase A (PKA) is a family of serine-threonine kinase [1] whose activity is dependent on cellular levels of cyclic AMP (cAMP). PKA is also known as cAMP-dependent protein kinase (EC 2.7.11.11). PKA has several functions in the cell, including regulation of glycogen, sugar, and lipid metabolism.
Sam Smith, left, and Kesha attend the Christian Cowan fashion show during New York Fashion Week on Feb. 7, 2025, in New York City.
When dissociated, the diisopropylamide anion can become protonated to form diisopropylamine. Diisopropylamine has a p K a value of 36. Therefore, its conjugate base is suitable for the deprotonation of compounds with greater acidity, importantly, such weakly acidic compounds (carbon acids) of the type HC(Z)R 2 , where Z = C(O)R', C(O)OR' or CN.