This is from my ochem lab. I filled in the parts that I could from the lab and t

Question

This is from my ochem lab. I filled in the parts that I could from the lab and the procedure of the lab. Please answer the questions below. Thank you!

(4 pts) Carboxylic Acid mp after extraction a't identity mp after crystallization a 6°C Mass recovered from extraction 026 mass of pure % recovery from original mixture Structure: (show calculations) identity (4 pts)Amine mp after extraction C Mass recovered from extraction , 2 % recovery from original mixture Structure (show calculations) (4 pts)Non-Ionizable Compound identity mp after extraction 83e mp after crystallization 76°C Mass recovered from extraction 0.I52 mass of pure commpound .082 (show calculations) % recovery from original mixture Structure:

Explanation / Answer

Carboxylic acid

% recovery from original mixture=(mass of pure compound/mass recovered from extraction)*100=(0.14/0.2)*100=70%

Amine

% recovery from original mixture=(mass of pure compound/mass recovered from extraction)*100=(not given/0.2)*100=0

Non-ionizable compound

% recovery from original mixture=(mass of pure compound/mass recovered from extraction)*100=(0.032/0.15)*100=21.3%

1) % of material not recovered from original sample=100-percent recovered

for carboxylic acid ,% of material not recovered from original sample=100-70=30%

Amine,

% of material not recovered from original sample=100-0=100%

non-ionizable compound=100-21.3=78.7%

2)Low recovery of non-ionizable compounds has been observed.

Possible reason must be due to errors in crystallization methods:

1) Impure compound dissolved in relatively large amount of solvent so loss of mass of the recrystallized compound may have occured.Rather it must be dissolved in minimum amount of solvent for easy recovery by crystallization

2) Loss of dissolved compound due to transfer or spills

3) Improper recrystallization of pure compound due to improper dissolving solvent used.The solute may be soluble in the solvent to some degree even on cooling the solution.Ideal solvent for recrystallization is one that retains the solute only at high temperatures and throw out all the solute on cooling due to decreased solubility.

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