Possible Exp. 3 Questions Flashcards
(34 cards)
Extraction is an isolation technique used to separate compounds based on their ______.
Solubility in various media
What is an everyday use of extraction?
Making coffee
What are the types of extraction? (There are 3)
Solid/liquid, liquid/liquid, and acid/base
What is an example of solid/liquid extraction?
Extracting flavor and odor components of dried vegetable matter using hot water
In a liquid/liquid extraction, what kinds of products must be separated?
Organic products must be separated from inorganic products
How can one extract the organic product from a liquid/liquid extraction?
Using an organic solvent
Why is an organic solvent used?
To dissolve the organic products. The inorganic products will not dissolve into the organic solvent. The organic solvent will separate out and form an organic layer, which can then be removed and evaporated to leave just the organic product
What is the goal of liquid/liquid extraction?
To separate organic products from inorganic products using an organic solvent
What is an example of a common organic solvent?
Ether
What is the goal of acid/base extraction?
To separate strong organic acids, weak organic acids, neutral organic compounds, and basic organic substances
What kinds of extraction are used most in organic reactions?
Liquid/liquid and acid/base
What are the properties of a good solvent?
Should easily dissolve the substance being extracted, low boiling point, not react with the solute or other solvents, nonflammable and nontoxic, inexpensive, and MOST IMPORTANTLY shouldn’t be miscible with water
What is the most important property of a good solvent?
It is not miscible with water
What extraction solvent was used in the experiment?
Ether
What kinds of extraction were conducted in the experiment?
Solid/liquid and liquid/liquid
What is an emulsion?
A suspension of one liquid as droplets in another
Are emulsions stable?
YES. They are very stable, once they are formed
How can one avoid an emulsion?
Gently shake the solution to be extracted and let it stand until the two layers can be seen to clearly have separated. Making the aqueous layer very ionic will also help to prevent emulsions from forming
How can one break down an emulsion?
Vacuum filtration and centrifugation
How does pressure build up in an extraction mixture that contains a very volatile solvent?
The heat of the acid/base reactions or the heat of the hand
What must be done to avoid pressure buildup?
Frequent ventilation
In this lab, what caused pressure buildup?
The addition of sodium bicarbonate. Carbon dioxide formed and caused pressure buildup.
Why are drying agents necessary?
To remove the little bit of water that is dissolved by the organic solvents
What are the properties of a good drying agent?
Will not react with the compound being extracted, will remove the water fast from the solvent, must be very efficient, and must not get in the way in the ease of recovery of the compound
