curves in part a(i)‚ a(ii) and a(iii) do have a flat section. These indicate that the boiling point has been reached‚ as the temperature remains constant until the volume of the water decreases by 50ml. This indicates that the vapour pressure has reached the external pressure thus resulting in water boiling (Vaclavik & Christian‚ 2008). The temperature remains constant because the excess energy put in is used to meet the energy requirement for the change between liquid and gaseous state‚ in which
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Experiment 3: Cryoscopic Determination of Molecular Weight Aim: The primary objective of the experiment is to calculate the total molecular mass of the compound benzoic acid in a predetermined amount of cyclohexane. Introduction: One of the key concepts in this experiment is the term freezing point depression. The definition of this phrase is that when a solute is dissolved into a solvent‚ their collective boiling point will be less than that of the original boiling point of the solvent. This incidentally
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The vapor pressure of a liquid is the equilibrium pressure of gas molecules from that liquid (i.e.‚ the results of evaporation) above the liquid itself. A glass of water placed in an open room will evaporate completely (and thus never reach equilibrium); however‚ if a cover is placed on the glass‚ the space above the liquid will eventually contain a constant amount of water vapor. How much water vapor is present depends on the temperature‚ but not on the amount of liquid that is present at equilibrium
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heating a substance until it is vaporized‚ cooling the vapors‚ and collecting the condensed liquid is the basis of a commonly used purification technique called distillation. Vapor Pressure and Boiling Point If a liquid is placed in a closed container‚ some molecules at the surface of the liquid evaporate into the space above the liquid. If this didn’t happen‚ you wouldn’t be able to smell a liquid. Once vaporized‚ some of the molecules in the vapor condense back into the liquid in a competing process
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Experiment 2: Isolation of Eugenol from Cloves Background; Readings on Vapor pressure‚ Raoult’s Law from TRO: A mixture of the essential oils‚ eugenol and acetyleugenol‚ will be steam distilled from cloves. These compounds are isolated from aqueous distillate by extraction into dichloromethane. The dichloromethane solution is shaken with aqueous sodium hydroxide‚ which will react with eugenol‚ to yield the sodium salt of eugenol in the basic
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Temperature and Humidity Lab Name__ __________________ This activity will look at two of the most fundamental and important elements of weather: temperature and humidity. Objectives: 1. The students will discover the need for measuring instruments to quantify weather observations. 2. The students will learn how to use a sling psychrometer to determine temperature and relative humidity values. 3. The students will explain and understand the difference between absolute and relative
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property of changing readily from a solid or liquid to a vapor or the tendency of a substance to vaporize. It is directly related to a compounds vapor pressure. A compound with higher vapor pressure vaporizes sooner than a compound with a lower vapor pressure. In the course of distillation the substances are heated to a boiling point in a glass container known as the pot. A condenser that is cooled by flowing water is used to cool the vapors produced as they re-liquefy and are collected in a separate
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Experiment In this experiment a high vacuum sublimation was performed to determine the vapor pressure and finally the enthalpy of sublimation of Vanillin and o-Vanillin. AKnudsen cell with sample was weighed 10 times maybe just say weighed by difference‚ they don’t usually like it when you spell out the steps like that no way it was like 0.5 grams‚ check the lab again and at least 0.5 g of Vanillin or o-Vanillin was added to the cell and it was reweighed 10 times. This experiment depended heavily
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toluene. Post Lab: At any given temperature a liquid is in equilibrium with its vapor. This equilibrium is described by the vapor pressure of the liquid. The vapor pressure is the pressure that the molecules at the surface of the liquid exert against the external pressure; this is usually the atmospheric pressure. Vapor pressure does not increase linearly but instead‚ increases exponentially with temperature. The vapor pressure of a substance roughly doubles for every
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Properties & Osmotic Pressure Peter Jeschofnig‚ Ph.D. Version 42-0149-00-01 Lab RepoRt assistant This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions‚ diagrams if needed‚ and data tables that should be addressed in a formal lab report. The intent is to facilitate student’s writing of lab reports by providing this
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