Intermolecular Forces Of Attraction - ProProfs Quiz
Practice Quiz 2. 1. The intermolecular forces that are most significant in accounting for the high boiling point of liquid water relative to other substances of similar. AP Chemistry - Unit 7 Group Quiz. Alt SCN0.)! 9M The vapor pressure and boiling point of the solution will be higher than that of the pure solvent. b/ The vapor. Start studying Chemistry Quiz: Intermolecular Forces. Learn vocabulary, terms What is the relationship between intermolecular forces and boiling point? Direct.
For these molecules, the applicable intermolecular interactions are dipole and induced dipole interactions. The induced dipole or dispersion interactions increase with molecular weight. Dipole-dipole interactions are also important for these interhalogen compounds; their bond dipoles do not cancel thereby giving rise to a permanent dipole. Considering the electronegativity differences in the compounds and hence the magnitude of the bond dipoles, IF5 is expected to have the strongest dipole-dipole interactions, followed by BrF5, and the weakest interactions are expected with ClF5.
Ordering of boiling points: The greater the attractive interactions, the higher the boiling point. Before discussing intermolecular interactions, it is first necessary to introduce the idea of a dipole.
Intermolecular forces and liquids quiz Flashcards by Tres Schuler | Brainscape
A dipole can be represented as two charges, equal in magnitude but opposite in sign, at a fixed distance from one and other. The positive end of one dipole interacts attractively with the negative end of another dipole and vice versa.
The electron density of atoms is continuously fluctuating. Thus, at any given instant the electron density about an atom may be asymmetrically distributed thus giving rise to a transient dipole see Figure below.
A snapshot in time of two Ar atoms. The shading represents the instantaneous electron density about the atoms. The deltas indicate the partial charge distribution. The arrow with a plus symbol on its tail is a symbol for a dipole note the orientation relative to the specifed partial charges.
It is important to realize that these are not permanent dipoles, they are transient since the electron density is continually fluctuating. Despite this continual fluctuation, the net result is an attractive interaction. Induced dipole interactions are also termed dispersion interactions, and they result in the condensation of noble gases such as Ar or Ne.
Ne has a lower boiling point than Ar because dispersion interactions increase with increasing molecular weight.
How are vapor pressure and boiling point related?
In small atoms, the electrons are held tightly by the nucleus and are not as readily polarized distorted as in larger atoms with electrons further from the nucleus. The same shaped graph line examples below for pure liquids is obtained with any liquid, though the relative position of the curve depends on the volatility of the liquid, which in turn depends on the strength of the inter—molecular attractive forces see later paragraph.
Liquids containing dissolved substances i. Typical saturated vapour pressure curves max.
How do intermolecular forces affect vapor pressure?
The vapour pressure curves are shown in the graph above for When the vapour pressure of a liquid matches the ambient pressure, the liquid boils as bubbles of vapour can now form in the bulk liquid.
This has consequences for brewing a cup of tea as you climb a high mountain. It gets more and more difficult to brew a good pot of tea because the boiling temperature gets lower and lower as the pressure falls with increasing height! Note on some applications of vapour pressure data: A knowledge of vapour pressures from data tables is important is understanding and using the technique known as steam distillation, described in section 8.
You can also distil thermally unstable compounds at a more lower temperature than its normal boiling point at normal atmospheric pressure by means of reduced pressure distillation 'vacuum distillation'. If you reduce the pressure in the flask and condenser system, you then reduce the vapour pressure needed for the liquid to boil i.