CHEM 2211 Lab Final UGA Exam Questions
With Accurate Answers
Recrystallization - ANSWER a technique used to purify organic solid compounds with the
goal to dissolve and subsequently crystallize a pure substance from the solution.
What are the four characteristics of a good solvent? - ANSWER -Target must be soluble
in high temp with impurities soluble at room temp or at high temps
-Must be chemically inert (non-reactive)
-Low boiling point, or highly volatile
What are the 5 basic steps to Recrystallization - ANSWER -Choose suitable solvent
-Dissolve the impure mixture in the hot solvent
-Remove the insoluble impurities via high temp gravity filtration
-Cool the solution to induce recrystallization
-Isolate pure crystals via suction filtration
If crystals do not form, what went wrong? How do you fix it? - ANSWER Too much
solvent was used. Boil the solvent off and try to recrystallize again
How do impurities affect the Melting Point of a compound? - ANSWER Impurities both
broaden and depress a pure compounds melting point range.
, What is the eutectic point? - ANSWER The Lowest possible melting point of a mixture of
substances
What kind of Melting Point did you conduct to verify your unknown? - ANSWER A 50:50
Mixed Melting point
How do you induce recrystallization? - ANSWER Bring to room temperature, Scratch
inside flask walls, Ice baths
Distillation - ANSWER process of separating the component substances from a liquid
mixture by selective evaporation and condensation. Distillation may result in essentially
complete separation
What are the two types of distillation? - ANSWER Simple and Fractional
How is separation achieved? - ANSWER based on the difference in boiling point of
miscible (able to mix in all proportions) liquids
Dalton's Law - ANSWER The total vapor pressure exerted by a solution at a given
temperature is equal to the sum of the partial vapor pressures of individual components.
Pt= Pa + Pb + Pc
Raoult's Law - ANSWER Partial vapor pressure of each component in a solution is equal
With Accurate Answers
Recrystallization - ANSWER a technique used to purify organic solid compounds with the
goal to dissolve and subsequently crystallize a pure substance from the solution.
What are the four characteristics of a good solvent? - ANSWER -Target must be soluble
in high temp with impurities soluble at room temp or at high temps
-Must be chemically inert (non-reactive)
-Low boiling point, or highly volatile
What are the 5 basic steps to Recrystallization - ANSWER -Choose suitable solvent
-Dissolve the impure mixture in the hot solvent
-Remove the insoluble impurities via high temp gravity filtration
-Cool the solution to induce recrystallization
-Isolate pure crystals via suction filtration
If crystals do not form, what went wrong? How do you fix it? - ANSWER Too much
solvent was used. Boil the solvent off and try to recrystallize again
How do impurities affect the Melting Point of a compound? - ANSWER Impurities both
broaden and depress a pure compounds melting point range.
, What is the eutectic point? - ANSWER The Lowest possible melting point of a mixture of
substances
What kind of Melting Point did you conduct to verify your unknown? - ANSWER A 50:50
Mixed Melting point
How do you induce recrystallization? - ANSWER Bring to room temperature, Scratch
inside flask walls, Ice baths
Distillation - ANSWER process of separating the component substances from a liquid
mixture by selective evaporation and condensation. Distillation may result in essentially
complete separation
What are the two types of distillation? - ANSWER Simple and Fractional
How is separation achieved? - ANSWER based on the difference in boiling point of
miscible (able to mix in all proportions) liquids
Dalton's Law - ANSWER The total vapor pressure exerted by a solution at a given
temperature is equal to the sum of the partial vapor pressures of individual components.
Pt= Pa + Pb + Pc
Raoult's Law - ANSWER Partial vapor pressure of each component in a solution is equal
