| Popis: |
Using a modified form of the Ostwald viscosimeter, viscosity-measurements have been carried out over a temperature-range from the melting points up to about 20°C for the two isomers of 1,2-dichloroethene. Densitymeasurements were made over the same range of temperature. Special care has been taken in purifying the samples used. From the data obtained, values of the free energy, the energy and the entropy of activation for viscous flow have been calculated, using the theory of Eyring. It appears that the experimental quantity Evis, defined by , has a temperature-independent value of about the same magnitude for both isomers, whereas Eyring's “energy of activation for viscous flow” is temperature-dependent. It is concluded that both isomers behave as normal unassociated substances, which conclusion is reached as well from consideration of the values of the “rheochor” and from the relation between the surface tension and Evis. |
