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The van 't Hoff factor i (named after Dutch chemist Jacobus Henricus van 't Hoff) is a measure of the effect of a solute on colligative properties such as osmotic pressure, relative lowering in vapor pressure, boiling-point elevation and freezing-point depression.
Jacobus van 't Hoff found a quantitative relationship between osmotic pressure and solute concentration, expressed in the following equation: Π = i c R T {\displaystyle \Pi =icRT} where Π {\displaystyle \Pi } is osmotic pressure, i is the dimensionless van 't Hoff index , c is the molar concentration of solute, R is the ideal gas constant ...
The Van 't Hoff equation relates the change in the equilibrium constant, K eq, of a chemical reaction to the change in temperature, T, given the standard enthalpy change, Δ r H ⊖, for the process. The subscript r {\displaystyle r} means "reaction" and the superscript ⊖ {\displaystyle \ominus } means "standard".
For instance, for solutions of magnesium chloride, the vapor pressure is slightly greater than that predicted by Raoult's law up to a concentration of 0.7 mol/kg, after which the vapor pressure is lower than Raoult's law predicts. For aqueous solutions, the osmotic coefficients can be calculated theoretically by Pitzer equations [4] or TCPC model.
In 1878, van 't Hoff married Johanna Francina Mees. They had two daughters, Johanna Francina (1880–1964) and Aleida Jacoba (1882–1971), and two sons, Jacobus Henricus van 't Hoff III (1883–1943) and Govert Jacob (1889–1918). Van 't Hoff died at the age of 58, on 1 March 1911, at Steglitz, near Berlin, of tuberculosis.
Similarly, the combined ideal gas law, =, has as an analogue for ideal solutions =, where is osmotic pressure; V is the volume; n is the number of moles of solute; R is the molar gas constant 8.314 J K −1 mol −1; T is absolute temperature; and i is the Van 't Hoff factor. The osmotic pressure is then proportional to the molar concentration ...
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. Through cryoscopy, a known constant can be used to calculate an unknown molar mass. The term "cryoscopy" means "freezing measurement" in Greek.
Water potential is the potential energy of water per unit volume relative to pure water in reference conditions. Water potential quantifies the tendency of water to move from one area to another due to osmosis, gravity, mechanical pressure and matrix effects such as capillary action (which is caused by surface tension).