酸碱指示剂的变色范围是pH=pKaθ(HIn)±1。 参考答案:对 点击查看答案 你可能感兴趣的试题 单项选择题 All else constant, a bond will sell at ___ when the coupon rate is ___ the yield to maturity. ( ) A. a premium; less than B. a premium; equal to C. a discount; less than D. ...
pKa and pH - The fundamental distinction between pKa and pH is that pKa denotes an acid's dissociation, whereas pH denotes a system's acidity or alkalinity.
In solutions where the pH is less than the pKa value, amine groups exist as protonated amine (–NH3+) groups on the BDD surface. As more H+ ions bond to the amine groups to form Sensors 2018, 18, 2178 7 of 10 (–NH2) or protonated amine (–NH3+) groups, with typical pKa values...
As a result, there is an increase in (i) the hydrophilic nature of the hydrogels, (ii) the number of fixed negative charges, and (iii) the electrostatic repulsion between the chains leading to swelling of the hydrogel network and vice versa (when the pH is less than the pKa). On the...
The term "pH" is a measure ofhydrogenionconcentration, a quantitative measure of theacidityoralkalinityof asolution. In chemistry, the pH scale usually ranges from 0 to 14.Aqueous solutionsat 25°C with a pH of less than 7 areacidic, while those with a pH greater than 7 are basic oralk...
Upon TNF treatment, overexpression of non-phosphorylatable mutant of PHF20 (PHF20/S291A) also enhanced persistent p65 phosphorylation as well as NF-kB reporter activity, but to a less extent than the wild-type PHF20 or PHF20/S265A (Supplementary Fig. S6b,c). Similar effects of wild- ...
A high skin friction cosmetic composition that can provide the consumer-desired sensory properties of traditional vanishing creams, stable at low pH, containing solid asymmetric particles and an anionic emulsifier having pKa values of less than about 4.5. The composition preferably further includes an ...
The pKa values that correspond to these groups are pKaCOO−=5 [57] and pKaNH3+=9 [34]. Eqs. (4a), (4b) contain the parameters σnmax and σpmax, respectively, that are determined by the maximal possible densities of these groups on the nanopore's surface. The values we used (σ...
Most notable is the E247 with a decrease of the calculated pKa from 5.2 ± 2.5 to 3.7 ± 1.1. This suggests that the glutamate is less likely to be protonated in Y406A at higher pH values and thus more likely to form interactions with neighboring residues and Na+ ...
For these types of applications, fluorescein conjugates are less than optimal because they have little sensitivity in the pH range below pH 5.5. The response range can be extended using conjugates of our Oregon Green 488 dye, which has a much lower pKa than fluorescein (4.7 compared with ...