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Caffeine Properties Chemical formula. C 8 H 10 N 4 O 2: Molar mass: 194.194 g·mol −1 Appearance Odorless, white needles or powder Density: 1.23 g/cm 3, solid [1]
In chemistry, protonation (or hydronation) is the adding of a proton (or hydron, or hydrogen cation), usually denoted by H +, to an atom, molecule, or ion, forming a conjugate acid. [1] (The complementary process, when a proton is removed from a Brønsted–Lowry acid, is deprotonation.) Some examples include The protonation of water by ...
The conjugate acid in the after side of an equation gains a hydrogen ion, so in the before side of the equation the compound that has one less hydrogen ion of the conjugate acid is the base. The conjugate base in the after side of the equation lost a hydrogen ion, so in the before side of the equation, the compound that has one more hydrogen ...
1,3,7-Trimethyluric acid is a minor caffeine metabolite. [5] 7-Methylxanthine is also a metabolite of caffeine. [193] [194] Each of the above metabolites is further metabolized and then excreted in the urine. Caffeine can accumulate in individuals with severe liver disease, increasing its half-life. [195]
A simple buffer solution consists of a solution of an acid and a salt of the conjugate base of the acid. For example, the acid may be acetic acid and the salt may be sodium acetate . The Henderson–Hasselbalch equation relates the pH of a solution containing a mixture of the two components to the acid dissociation constant , K a of the acid ...
1,3,7-Trimethyluric acid, also referred to as trimethyluric acid and 8-oxy-caffeine, is a purine alkaloid that is produced in some plants and occurs as a minor metabolite of caffeine in humans. [1] The enzymes that metabolize caffeine into 1,3,7-trimethyluric acid in humans include CYP1A2 , CYP2E1 , CYP2C8 , CYP2C9 , and CYP3A4 .
Therefore, the side of the equation with water will be formed preferentially. If, for example, water, instead of hydroxide, was used to deprotonate the carboxylic acid, the equilibrium would not favor the formation of the carboxylate salt. This is because the conjugate acid, hydronium, has a pK a of -1.74, which is lower than the carboxylic ...
In the case of citric acid, the overlap is extensive and solutions of citric acid are buffered over the whole range of pH 2.5 to 7.5. Calculation of the pH with a polyprotic acid requires a speciation calculation to be performed. In the case of citric acid, this entails the solution of the two equations of mass balance: