Term
| Upon what does the separation of two or more liquid compounds by distillation depend? |
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Definition
| Boiling point differences |
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Term
| What is meant by the term vapor pressure? |
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Definition
| The pressure exerted by a liquid on its environment |
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Term
| How is the boiling point of a pure liquid definted? |
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Definition
| The temperature where the liquids vapor pressure equals the pressure exerted by the atmosphere |
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Term
| In a collection of compounds of similar molecular weight which will have the higher boiling points and which will have a lower boiling point? |
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Definition
| High Boiling point (Polar compounds)<----------Lower boiling point (Nonpolar compounds) |
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Term
| Upon what does the boiling point a mixture depend? |
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Definition
| Upon the vapor pressures of teh various components |
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Term
| what affects can impurities have on the observed boiling point? |
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Definition
| The observed boiling point will be either higher or lower |
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Term
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Definition
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Term
| What distinguishes simple distillation from fractional? |
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Definition
-The number of vaporization-condesation cycles (Theoretical plate)
-Simple distilations typically have 1-2 vap-condensation cycles.
-Fractional distilations have 3 or more vaporization-condensation cycles |
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Term
| What is meant by the term distillate? |
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Definition
| Refers to the condensed liquid |
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Term
| During distillation how does teh boiling point of the liquid remaining in the distilling flask change? |
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Definition
| The liquid remaining in the flask becomes richer in the less volatile compound |
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Term
| During distillation how does the boiling point of the liquid remaining in the distilling flask change? |
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Definition
| The boiling point of the liquid remaining in the distilling flask rised during the course of the distillation |
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Term
| Under what circumstances is simple distillation commonly employed? |
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Definition
A) To purify an organic compound and determines its boiling point.
B) To sepatate a high boiling organic compound from a low boiling organic solvent. |
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Term
| to what level should one fill the distilling flask prior to starting a simple distillation? |
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Definition
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Term
| How does one know whether or not the thermometer is positioned correctly in the distilling head of a distillation apparatus? |
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Definition
| The top of the thermometer bulb should be level with the bottom of the three wat adapters side arm |
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Term
| How should the distilling flask.three-way adapter assembly by positioned? |
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Definition
| The distilling flask/three-way adapter assembly should be positioned vertically |
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Term
| How is heat input to the distilling flask from the heating mantle controlled? |
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Definition
| Heat input is controlled by a variable transformer |
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Term
| when should a distillation be stopped? |
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Definition
| Before the distilling flask reaches dryness |
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Term
| Upon what does the efficiency of a fractionating column depend? |
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Definition
| The number of vaporization-condensation cycles (Theoretical plates) |
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Term
| what rate of distillate collection indicates a slow, steady distillation? |
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Definition
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Term
| How does the use of excessive heat affect fractional distillation? |
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Definition
| The number of possible vaporization-condensation cycle decreases and separation is compromised |
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Term
| How does the use of too little heat affect fractional distillation? |
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Definition
| The fractioning column loses more heat than the ascending |
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