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The entropy of vaporization of XeF 6 at its boiling point has the extraordinarily high value of 136.9 J/(K·mol) or 16.5 R. [4] The characteristic of those liquids to which Trouton’s rule cannot be applied is their special interaction between molecules, such as hydrogen bonding. The entropy of vaporization of water and ethanol shows positive ...
Ethanol and dimethyl ether, two chemicals with the same formula (C 2 H 6 O), have different volatilities due to the different interactions that occur between their molecules in the liquid phase: ethanol molecules are capable of hydrogen bonding while dimethyl ether molecules are not. [4] The result in an overall stronger attractive force ...
The study also supports the fact that ethanol prefers to bond just below the hydrophilic region of the phospholipids near the phosphate groups. The location of the ethanol creates a strong hydrogen bond between the water molecules. [3] The results are depicted in the simulations and supported by mass density profiles as well.
An ubiquitous example of a hydrogen bond is found between water molecules. In a discrete water molecule, there are two hydrogen atoms and one oxygen atom. The simplest case is a pair of water molecules with one hydrogen bond between them, which is called the water dimer and is often used as a model system. When more molecules are present, as is ...
Because of hydrogen bonding, alcohols tend to have higher boiling points than comparable hydrocarbons and ethers. The boiling point of the alcohol ethanol is 78.29 °C, compared to 69 °C for the hydrocarbon hexane, and 34.6 °C for diethyl ether.
Simple carboxylic acids dimerize by forming hydrogen bonds between molecules. A minor factor affecting boiling points is the shape of a molecule. Making the shape of a molecule more compact tends to lower the normal boiling point slightly compared to an equivalent molecule with more surface area.
The result is that in dilute ideal solutions, the extent of boiling-point elevation is directly proportional to the molal concentration (amount of substance per mass) of the solution according to the equation: [2] ΔT b = K b · b c. where the boiling point elevation, is defined as T b (solution) − T b (pure solvent).
Mixing equal volumes of ethanol and water results in only 1.92 volumes of mixture. [75] [80] Mixing ethanol and water is exothermic, with up to 777 J/mol [81] being released at 298 K. Hydrogen bonding in solid ethanol at −186 °C. Hydrogen bonding causes pure ethanol to be hygroscopic to the