A liquid-liquid extraction was performed by a student to remove caffeine from a freshly brewed pot of coffee. In the separatory funnel, the student added the coffee and extracted the caffeine using dichloromethane (d = 1.33g/mL). After shaking and venting, two layers formed, the student then proceeded to drain the bottom layer into a flash labeled flask #1. Which of the following is the best explanation as to what the student should do next?
a)Discard the contents of flask #1 as it does not contain the product, instead add the remaining liquid in the separatory funnel to a new flask and proceed to extract the caffeine.
b) Add acid to the remaining contents in the separatory funnel, then add to a new flask
c)Add a drying agent to flask #1, filter, then evaporate to obtain solid caffeine.
d)Add water to flask # 1 and evaporate
In general, for an acid or base liquid-liquid extraction we generate some type of salt. We take advantage of the fact that this salt is ____ soluble in the water because it is ____.
a)less, polar
b) less, nonpolar
c) more, polar
d) more, nonpolar
can you please explain this quesiton to me and give me the answer?
also can you check this? I think the answer is c
For a melting point determination, if the compound is less pure, then the melting point will generally be higher or lower and why?
a. Higher, impurities may react to for liquids which do not dissipate at room temperature
b. Lower, because defects in a crystal lattice require less energy to break the lattice
c. Lower, impurities may react to form gasses which dissipate at room temperature
d. Higher, additional defects will be harder to melt
A liquid-liquid extraction was performed by a student to remove caffeine from a freshly brewed pot of coffee. In the separatory funnel, the student added the coffee and extracted the caffeine using dichloromethane (d = 1.33g/mL). After shaking and venting, two layers formed, the student then proceeded to drain the bottom layer into a flash labeled flask #1. Which of the following is the best explanation as to what the student should do next?
| a)Discard the contents of flask #1 as it does not contain the product, instead add the remaining liquid in the separatory funnel to a new flask and proceed to extract the caffeine. |
| b) Add acid to the remaining contents in the separatory funnel, then add to a new flask |
| c)Add a drying agent to flask #1, filter, then evaporate to obtain solid caffeine. |
| d)Add water to flask # 1 and evaporate |
In general, for an acid or base liquid-liquid extraction we generate some type of salt. We take advantage of the fact that this salt is ____ soluble in the water because it is ____.
| a)less, polar |
| b) | less, nonpolar |
| c) | more, polar |
| d) | more, nonpolar |
can you please explain this quesiton to me and give me the answer?
also can you check this? I think the answer is c
For a melting point determination, if the compound is less pure, then the melting point will generally be higher or lower and why?
| a. | Higher, impurities may react to for liquids which do not dissipate at room temperature |
| b. | Lower, because defects in a crystal lattice require less energy to break the lattice |
| c. | Lower, impurities may react to form gasses which dissipate at room temperature |
| d. | Higher, additional defects will be harder to melt |
Related textbook solutions
Basic Chemistry
Principles of Chemistry Molecular Approach
Chemistry: Structure and Properties
Principles of Chemistry Molecular Approach
Chemistry: A Molecular Approach
Chemistry: A Molecular Approach
Principles of Chemistry: A Molecular Approach
