Colligative Properties Boiling Point

Co to http //now.brookscole.com/ cracoliceSe and click Coached Problems for an exercise on Colligative Properties Boiling Point and Freezing Point. 

Another application of a power series in physical chemistry is in the discussion of colligative properties (freezing-point depression, boiling-point elevation, and osmotic pressure). If is the mole fraction of solvent, AyapHm is the molar heat of vaporization of the solvent, Tq is the pure solvent s boiling temperature, and T is the solution s boiling temperature, it is shown in physical chemistry textbooks that... 

Methods that depend on end-group analysis or colligative properties (freezing-point depressirai, boiling-point elevation, osmotic pressure) can be employed to determine M . 

BoUmg-point elevation Colligative properties Freezing-point depression MoM boiling-point elevation constant... 

M depends not on the molecular sizes of the particles but on the number of particles. Measuring colligative properties such as boiling point elevation, freezing point depression, and vapor pressure lowering can determine the number of particles in a sample. 

The properties of a solution differ considerably from those of the pure solvent Those solution properties that depend primarily on the concentration of solute particles rather than their nature are called colligative properties. Such properties include vapor pressure lowering, osmotic pressure, boiling point elevation, and freezing point depression. This section considers the relations between colligative properties and solute concentration, with nonelectrolytes that exist in solution as molecules. 

Boiling point elevation and freezing point lowering, like vapor pressure lowerings are colligative properties. They are directly proportional to solute concentration, generally expressed as molality, m. The relevant equations are... 

In physical chemistry, we apply the term colligative to those properties that depend upon number of molecules present. The principal colligative properties are boiling point elevation, freezing point depression, vapour pressure lowering, and osmotic pressure. All such methods require extrapolation of experimental data back to infinite dilution. This arises due to the fact that the physical properties of any solute at a reasonable concentration in a solvent are... 

The dissolution of a solute into a solvent perturbs the colligative properties of the solvent, affecting the freezing point, boiling point, vapor pressure, and osmotic pressure. The dissolution of solutes into a volatile solvent system will affect the vapor pressure of that solvent, and an ideal solution is one for which the degree of vapor pressure change is proportional to the concentration of solute. It was established by Raoult in 1888 that the effect on vapor pressure would be proportional to the mole fraction of solute, and independent of temperature. This behavior is illustrated in Fig. 10A, where individual vapor pressure curves are... 

The depression of a melting point is one of the simplest manifestations of a colligative property. Other everyday examples include pressure, osmotic pressure, vapour pressure and elevation of boiling point. 

But salted water boils at a higher temperature than does pure water, so the food cooks more quickly. (We saw on p. 203 how a hotter temperature promotes faster cooking.) The salt causes an elevation of boiling point, which is another colligative property. We call the determination of such an elevation ebullioscopy. 

Methods for the determination of Molecular weight based on colligative property are vapour-pressure lowering, boiling point elevation (ebulliometry), freezing-point depression (cryoscopy), and the Osmotic pressure (osmometry). 

Colligative properties are those properties of solutions that depend on the number of solute particles present and not their identity. Colligative properties include vapor pressure lowering, freezing point depression, boiling point elevation, and osmotic pressure. Colloids are homogeneous mixtures, in which the solute particles are intermediate in size between suspensions and true solutions. We can distinguish colloids from true solutions by the Tyndall effect. 

Colligative properties may involve changes in the melting or boiling points. Changes cannot be measured only before and after values can be measured. In an experiment, A T is not measured. The freezing, or boiling, point of the solution is measured and compared to that of the pure solvent. The difference is then calculated. 

Activity data for electrolytes usually are obtained by one or more of three independent experimental methods measurement of the potentials of electrochemical cells, measurement of the solubility, and measurement of the properties of the solvent, such as vapor pressure, freezing point depression, boiling point elevation, and osmotic pressure. All these solvent properties may be subsumed under the rubric colligative properties. 

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