Intermolecular forces in a liquid

Molecules of liquid bromine also move about relatively freely, but there is not much empty space between molecules. A liquid cannot be compressed significantly by increasing the pressure, because its molecules are already in close contact with one another. Neither does a liquid expand significantly if the pressure is reduced, because the intermolecular forces in a liquid are large enough to prevent the molecules from breaking away from one another. 

The liquid boiling point is a measure of the strength of the intermolecular forces in a liquid. 

The stronger the intermolecular forces in a liquid, the lower its vapor pressure at a given temperature. The stronger the intermolecular forces, the more energy it requires to escape the liquid phase and enter the gas phase. 

A measure of the strength of intermolecular forces in a liquid is the molar heat of vaporization (AH ap), defined as the energy (usually in kilojoules) required to vaporize one mole of a liquid. The molar heat of vaporization is directly related to the strength of intermolecular forces that exist in the liquid. If the intermolecular attraction is strong, it takes a lot of energy to free the molecules from the liquid phase. Consequently, the liquid has a relatively low vapor pressure and a high molar heat of vaporization. 

What can we learn about the intermolecular forces in a liquid from the molar heat of vaporization ... 

What is the relationship between intermolecular forces in a liquid and the liquid s boiling point and critical temperature Why is the critical temperature of water greater than that of most other substances ... 

Which of the following properties indicates very strong intermolecular forces in a liquid (a) very low surface tension, (b) very low critical temperature, (c) very low boiling point, (d) very low vapor pressure... 

Thus, only choice (d) indicates strong intermolecular forces in a hquid. The other choices indicate weak intermolecular forces in a liquid. 

Because the solubility parameter reflects the intermolecular forces in a liquid, it is a very useful parameter. The total interaction between molecules in a liquid may be the result of dipole-dipole, London, and hydrogen-bonding interactions. Therefore, it is possible to separate the contributions from each type of interaction and express the solubility parameter as though it were a vector sum. The result is... 

What is the relationship between intermolecular forces in a liquid and the liquid s boiling point and critical temperature Why is the critical temperature of water greater than that of most other substances How do the boiling points and melting points of water and carbon tetrachloride vary with pressure Explain any difference in behavior of these two substances. Why is solid carbon dioxide called dry ice ... 

Another property determined by the magnitude of intermolecular forces in a liquid is viscosity. Viscosity, with units of N s/m, is a measure of a fluid s resistance to flow. The higher the viscosity, the more slowly a liquid flows. The viscosity of a liquid typically decreases with increasing temperature. The phrase slow as molasses in winter refers to the fact that molasses pours more slowly (has a higher viscosity) in cold weather. You may also have noticed that honey and maple syrup seem thinner when they are heated. 

The liquid boiling point is a measure of the strength of the intermolecular forces in a liquid. The boiling point of isomers is often related to the strength of their dipole-dipole interactions. 

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