plz help - org. chem lab...?!!?

Question

1. in using separatory funnel, why is it not correct to allow both the upper and lower layers to pass through the stem of the funnel?

2. upon what law or principle is extraction based?



please answer in details and if you can give me your sources, please do.
:-) thanks...

and reply as soon as possible.

Answer 1

1. You do not want both layers to pass through the stem of the funnel because you want to ensure both layers are separated. Also any residual material left from the lower layer will contaminate the upper layer if it is allowed to run through the stem after the layers are separated.

2. The extraction is based primarily on the partition coefficient of the solute between the two phases. The partition coefficient is the ratio of the the concentration of the solute between the two immiscible phases. See http://en.wikipedia.org/wiki/Partition_coefficient

Answer 2

Basically when you perform and extraction with a seperatory funnel, you use a solvent that will dissolve the solute that you are trying to extract from your sample. Usually you will use a polar and nonpolar solvent. An example would be water and methylene chloride or water and diethyl ether. When mixed the two solvents will seperate into two phases and come to equilibrium. Unless of course you get an emulsion. Pray you dont get one of those, they are a pain in the *** to deal with. Once you get to equilibrium you collect the layer that will contain the compound you are trying to extract. therefore if you allow both layers to go through then you are defeating the whold purpose of using a seperatory funnel.

The law or principle by which extraction is based. Hmm Steve Geo has it but I would like to add the concept of a partition coefficient.. A partition coefficient is the equilibrium distribution of a solute between the two liquid phases and the ratio of the solute's concentration in the upper phase to its concentration in the lower phase.

That a compound will distribute itself between two solvents according to its affinity for each

Answer 3

1. Because you want to separate, so let only the lower layer pass through. You want to keep the upper layer clean, if it's in diethyl ether. Or the lower layer, if it's your product in methylene chloride. You'll have a tough enough job cleaning up the lower layer and the upper layer apart.

2. That a compound will distribute itself between two solvents according to its affinity for each. Sorry. You have a lab manual and your lab instructor. I got my degree in 1964, and it's hard to remember how I know what I know.

Answer 4

1) Serially with different receiving vessels, sure. You don't want to pour the second phase out through through the top joint if it will entrain stopcock grease.

2) Like dissolves like. Theoretical plates.

Crack your textbook. Use Google. Save the drama for your mama, get down and PUSH. Bench time is living; everything else is waiting.

Answer 5

you're able to make polymer of Agarose. This polymer is used appreciably in organic and organic learn because of the fact of its neutrality and simplicity of starting to be. it somewhat is used to split DNA, RNA and different small molecules on the inspiration of their length. this is extensively utilized as a gelling agent for making dietary mediums for microbes or plant life. For making this polymer, take agarose or agar or agar agar, take around 0.5 to a million.5 g in 100ml of water(i.e. 0.5 to a million.5 %, quantity can variety) and boil it until eventually ultimately the agarose dissolves. Then flow away it to relax at RT. while it cools down you will see the polymer in type of gel.