chm-102 chm-102 uncw uncw intermolecular forces: evaporation of alcohols and alkanes general...
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Intermolecular Forces: Evaporation of Intermolecular Forces: Evaporation of Alcohols and AlkanesAlcohols and Alkanes
General Chemistry 101/102General Chemistry 101/102Laboratory ManualLaboratory Manual
University of North Carolina WilmingtonUniversity of North Carolina Wilmington
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Intermolecular ForcesIntermolecular Forces
• PurposePurpose To study the effects of Intermolecular Forces, the forces To study the effects of Intermolecular Forces, the forces
of attraction of attraction betweenbetween molecules, on the physical molecules, on the physical properties of alcohols and alkanes.properties of alcohols and alkanes.
• Safety ConsiderationsSafety Considerations Avoid inhaling the fumes from the alcohols and Avoid inhaling the fumes from the alcohols and
alkanes.alkanes. Wash the affected area thoroughly if you contact Wash the affected area thoroughly if you contact
any of the alcohols or alkanes.any of the alcohols or alkanes. Dispose of all liquid waste materials in the bottle Dispose of all liquid waste materials in the bottle
labeled “organic wastes” in the fume hood.labeled “organic wastes” in the fume hood.
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Intermolecular ForcesIntermolecular Forces
• ProcedureProcedure Connect the Tablet computer, Microlab unit, and Connect the Tablet computer, Microlab unit, and
the temperature probe as shown in the illustration the temperature probe as shown in the illustration below.below.
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Intermolecular ForcesIntermolecular Forces
• ProcedureProcedure To open the Intermolecular Forces experiment on the computer, To open the Intermolecular Forces experiment on the computer,
click on the Applications folder, and select the Microlab prompt. click on the Applications folder, and select the Microlab prompt. Then double click the “Time and Temperature” prompt as shown Then double click the “Time and Temperature” prompt as shown below.below.
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Intermolecular ForcesIntermolecular Forces
• ProcedureProcedure Click on the experiment entitled “Intermolecular Click on the experiment entitled “Intermolecular
Forces-Evaporative Cooling”, as shown below.Forces-Evaporative Cooling”, as shown below.
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Intermolecular ForcesIntermolecular Forces
• ProcedureProcedure
Place the temperature probe in the appropriate Place the temperature probe in the appropriate sample liquid and wait 45 seconds before starting sample liquid and wait 45 seconds before starting data collection. data collection.
Wrap 1” square of filter paper around temperature Wrap 1” square of filter paper around temperature probe and secure it with a small rubber band.probe and secure it with a small rubber band.
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Intermolecular ForcesIntermolecular Forces
• ProcedureProcedure
Click the “Start” Click the “Start” prompt to begin prompt to begin data collection data collection while the while the temperature temperature probe remains in probe remains in the liquid for the liquid for another 45 another 45 seconds. seconds.
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Intermolecular ForcesIntermolecular Forces• ProcedureProcedure
Remove the probe from the liquid and place it where it will remain undisturbed, such as on the lab bench or towards the inside of Remove the probe from the liquid and place it where it will remain undisturbed, such as on the lab bench or towards the inside of the sink, with the tip extending past the bench about 5 cm. Do not touch the temperature probe while the liquid is evaporating.the sink, with the tip extending past the bench about 5 cm. Do not touch the temperature probe while the liquid is evaporating.
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Intermolecular ForcesIntermolecular Forces• CalculationCalculation
Stop data collection when a minimum temperature has been reached.Stop data collection when a minimum temperature has been reached.
A
B
ΔT
The difference The difference in in
temperature temperature betweenbetweenpoint A point A
and point Band point Bis is ΔΔT for the T for the
sample solution.sample solution.