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Catechol (/ ˈ k æ t ɪ tʃ ɒ l / or / ˈ k æ t ɪ k ɒ l /), also known as pyrocatechol or 1,2-dihydroxybenzene, is an organic compound with the molecular formula C 6 H 4 (OH) 2. It is the ortho isomer of the three isomeric benzenediols .
IUPAC name IARC carcinogen group Toxic metabolite(s) Alcohol by volume (ABV) [1] LD50 in rat, oral [2]; Ethanol: Group 1: Acetaldehyde → acetic acid Up to 95.6% in rectified spirit
It is very difficult to measure pH values of less than two in aqueous solution with a glass electrode, because the Nernst equation breaks down at such low pH values. To determine pK values of less than about 2 or more than about 11 spectrophotometric [60] [61] or NMR [62] [63] measurements may be used instead of, or combined with, pH measurements.
The pH range is commonly given as zero to 14, but a pH value can be less than 0 for very concentrated strong acids or greater than 14 for very concentrated strong bases. [ 2 ] The pH scale is traceable to a set of standard solutions whose pH is established by international agreement. [ 3 ]
The ratio of concentration of conjugate acid/base to concentration of the acidic/basic indicator determines the pH (or pOH) of the solution and connects the color to the pH (or pOH) value. For pH indicators that are weak electrolytes, the Henderson–Hasselbalch equation can be written as: pH = pK a + log 10 [Ind −] / [HInd]
A basic formula [4] to calculate beer strength based on the difference between the original and final SG is: A B V = 131.25 ( O G − F G ) {\displaystyle ABV=131.25(OG-FG)} The formula below [ 5 ] is an alternate equation which provides more accurate estimates at higher alcohol percentages (it is typically used for beers above 6 or 7%).
Weighing hops. The chemical compounds in beer give it a distinctive taste, smell and appearance. The majority of compounds in beer come from the metabolic activities of plants and yeast and so are covered by the fields of biochemistry and organic chemistry. [1]
FDPB-based methods calculate the change in the pK a value of an amino acid side chain when that side chain is moved from a hypothetical fully solvated state to its position in the protein. To perform such a calculation, one needs theoretical methods that can calculate the effect of the protein interior on a p K a value, and knowledge of the pKa ...