Diethyl ether surface tension

Which of the following best explains why 1-butanol, CH3CH2CH2CH2OH, has a higher surface tension than its isomer, diethyl ether, CH3CH2OCH2CH3 ... 

E—The compound with the higher surface tension is the one with the stronger intermolecular force. The hydrogen bonding in 1-butanol is stronger than the dipole—dipole attractions in diethyl ether. 

Interfacial tension is the tension that is present at the interface of two immiscible phases and it has the same units as surface tension. The value of interfacial tension generally lies between the surface tension of two immiscible liquids as seen in Table 2.2, although it could also be lower than the surface tension of both liquids (water-diethyl ether). The interfacial tension between phases A and B, pab> is expressed by ... 

The PDMS objects assembled at the PFD/H20 interface upon agitation using an orbital shaker (Fig. 4.4). We chose this interface for four reasons, (i) PDMS does not swell in contact with either liquid, (ii) The interface has a high surface tension (y = 0.05 J m 2) for comparison, the H20/diethyl ether interface has a surface tension of y = 0.01 J m-2 [ref. 59]. Capillary forces are, thus, strong, (iii) PDMS (p = 1.05 g cirr3) has a density between those of PFD (p = 1.91 gcirr3) and water (p = 1.00 g cm-3) the objects floated at the interface, (iv) A thin film of PFD remained between the faces of objects when they assembled. This film acted as a lubricant and allowed the objects to move laterally relative to each other, and thus to minimize the free energy of the system. 

Materials. Sodium lauryl sulfate was purchased from Aldrich Chemical Company, Inc. and its constitution has been reported in detail (14). The material is a blend of C-12, C-14 and C-16 sodium sulfates. It was purified by extraction with diethyl ether and then by recrystallization from absolute ethanol. The surface tension of aqueous solutions of this material was measured as a function of concentration. A curve with a single break resulted indicating a CMC... 

Fig. 2C. 1. Static and dynamic surface tension of mixtures of diethyl ether and acetone vs. mol fraction of acetone...

C intervals). These authors have also given attention to the temperature coefficient, which, when plotted against mol.% of chloral, shows a maximum at 50 mol., corresponding to the formation of chloral hydrate, and two minima at approx. 18 and 8l mol.%, respectively. Ferroni et al.56 have also reported values for the surface tension of chloral hydrate solutions that range from 59-5 for 1 molar to 76.0 (dyne/cm.) at infinite dilution. Surface tension measurements made on solutions of chloral hydrate in diethyl ether, acetone, or benzene Olndicate weak compound formation in these systems. 

Water molecules can attract each other with strong hydrogen bonds diethyl ether molecules cannot (why ). The surface tension of water is greater than that of diethyl ether because of stronger intermolecular forces (the hydrogen bonds). 

Similar variations in the densities and surface tensions of mixtures are also known. The density of a mixture of bromo- and chlorobenzene is equal to the arithmetic mean of the densities of the individual components, whereas the density of trichloromethane-diethyl ether is about 1.5% above the mean value. The surface tensions of the systems diethyl ether-benzene and benzene-carbon disulfide are equal to the calculated values. The surface tension of methanol-ethyl iodide is greater and that of benzene-ethanol and acetone-carbon disulfide are less than the calculated values. 

By their nature, the experiments on gas bubble nucleation, whether electrolytic, chemically generated, or by pressure release, all have high concentrations of gas in solution during the bubble nucleation process, and thus show the most pronoimced effects of surface tension reduction. Two aspects of this observation are particularly noteworthy first, that He of all the gases so far tested shows the smallest ratio of theoryjmeasured—and is also the only gas with a b coefficient of 0. Second, that organic liquids with N2 gas dissolved in them (including the case of diethyl ether) show relatively modest ratios theoryjmeasured. In the case of diethyl ether, the liquid is relatively close... 

If we apply the ideas immediately above, the preferred surface structure would have the minimum surface energy. Comparing the surface tensions of the liquid phases associated with the vapors, we find that diethyl ether has the lowest surface tension. Thus, we suggest that the surface of NaCl might actually be covered with diethyl ether molecules. (Apart from its instructiveness, this example is extremely naive. In reality, ion-dipole interactions would contribute considerably to the formation of a molecular film on the surface of the solid. In extreme cases—like NaOH—energies of solvation are so negative that enough water is adsorbed to form a solution such compounds are described as deliquescent.)... 

The dispersion contribution to the surface tension of water estimated in Example 3.3 can generally be considered correct in the context of the Fowkes equation. Using this value, estimate with the Fowkes equation the interfacial tension of n-tetradecane (25.6)-water and diethyl ether (17)-water mixtures and compare them to the experimental values which are, respectively, 52 and 11. All surface tension values are given at mN and are at the same (room) temperature. Comment on the results. 

Both n-tetradecane and diethyl ether are non-polar fluids and we will assume that the whole surface tension contribution is due to dispersion forces. 

We wish to investigate whether this problem is due to the assumption we adopted for diethyl ether that all contributions to the surface tension are due to dispersion forces. If we use the Fowkes equation again assuming that the interfacial tension is known and back-calculate the dispersion value of diethyl ether s surface tension that would fit the experimental value we obtain ... 

Of course this value, which is almost equal to the surface tension of water ( ) and higher than the total surface tension of diethyl ether, has no physical meaning. Thus, the Fowkes equation clearly cannot be improved in this way and better theories are needed. 

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