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In thermodynamics, the ebullioscopic constant K b relates molality b to boiling point elevation. [1] It is the ratio of the latter to the former: = i is the van 't Hoff factor, the number of particles the solute splits into or forms when dissolved. b is the molality of the solution.
The K b values for dissociation of spermine protonated at one or other of the sites are examples of micro-constants. They cannot be determined directly by means of pH, absorbance, fluorescence or NMR measurements; a measured K b value is the sum of the K values for the micro-reactions.
For a strong acid-strong base titration monitored by pH, we have at any i'th point in the titration = [+] [] where K w is the water autoprotolysis constant.. If titrating an acid of initial volume and concentration [+] with base of concentration [], then at any i'th point in the titration with titrant volume ,
K b, the ebullioscopic constant, which is dependent on the properties of the solvent. It can be calculated as K b = RT b 2 M/ΔH v, where R is the gas constant, and T b is the boiling temperature of the pure solvent [in K], M is the molar mass of the solvent, and ΔH v is the heat of vaporization per mole of the solvent.
In chemistry and biochemistry, the Henderson–Hasselbalch equation = + ([] []) relates the pH of a chemical solution of a weak acid to the numerical value of the acid dissociation constant, K a, of acid and the ratio of the concentrations, [] [] of the acid and its conjugate base in an equilibrium.
To illustrate the processes, consider the case of dissolving a weak acid, HA, in water.The pH can be calculated using an ICE table. Note that in this example, we are assuming that the acid is not very weak, and that the concentration is not very dilute, so that the concentration of [OH −] ions can be neglected.
A smaller H + concentration means a greater OH − concentration and, therefore, a greater K b and a greater pH. NaOH (s) (sodium hydroxide) is a stronger base than (CH 3 CH 2) 2 NH (l) (diethylamine) which is a stronger base than NH 3 (g) (ammonia). As the bases get weaker, the smaller the K b values become. [1]
For bases, the base association constant, pK b is used. For any given acid or base the two constants are related by p K a + p K b = p K w , so p K a can always be used in calculations. On the other hand, stability constants for metal complexes , and binding constants for host–guest complexes are generally expressed as association constants.