Here are the essential concepts you must grasp in order to answer the question correctly.
Vapor Pressure
Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid or solid form at a given temperature. It indicates how readily a substance will evaporate; higher vapor pressure means a higher tendency to vaporize. In the context of solutions, the vapor pressure of a solvent decreases when a solute is added, which is crucial for understanding boiling point elevation.
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Boiling Point Elevation
Boiling point elevation is a colligative property that describes how the boiling point of a solvent increases when a solute is dissolved in it. This phenomenon occurs because the presence of solute particles disrupts the formation of vapor, requiring a higher temperature to reach the boiling point. The relationship can be quantified using the formula ΔT_b = i * K_b * m, where ΔT_b is the boiling point elevation, i is the van 't Hoff factor, K_b is the ebullioscopic constant, and m is the molality of the solution.
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Boiling Point Elevation Concept 1
Molality
Molality is a measure of concentration defined as the number of moles of solute per kilogram of solvent. It is expressed in mol/kg and is particularly useful in colligative property calculations, such as boiling point elevation and freezing point depression. Unlike molarity, molality is not affected by temperature changes, making it a stable measure for solutions in thermodynamic calculations.
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