Lab Final Flashcards
Desiccator
Provides storage for moister sensitive materials
ATAGO
refractometer- measures refractive index
Purpose of Steam Distillation
isolate essential oil from orange peels
Describe Process for Steam Distillation
Slurry Orange peels, set up apparatus, boil and liquid will drain into separatory funnel, aqueous layer in funnel is discarded, limonene is removed and dried using sodium sulfate, FTIR taken
What is the FTIR accessory used most in lab?
ATR
Benefits of using FTIR transmission vs ATR
Transmission- more distinct peaks because the light goes directly through sample in an enclosed space.
ATR is exposed to outside factors and light just goes through surface making it less distinct
What is FTIR used for?
To determine functional groups
Purpose of Thin Layer Chromatography
identify compounds present in mixture
How do you determine if the compounds are the same in TLC?
IF they have the same Rf values, however multiple compounds can have the same one
Purpose of 20% Ethyl acetate?
solution compounds were dissolved in.
What were the elutants in the lab and which one worked the best?
Hexane, 30% Ethyl acetate, 100% ethyl acetate
The 30% was the best because it contained both polar (ethyl acetate) and non-polar (hexane) components
What was the purpose of the foil
saturate the atmosphere to increase the possibility of reproducible results
Spotter
micropipette used to dispense samples using capillary action
UV lamp
used to track and see solvents on UV plate
Rf equation
Distance of sample/distance of solvent front
What is an indication of a sample having multiple components in TLC?
Multiple Rf values
Purpose of Gas Chromatography
Identify organic compounds in mixture
How does the GC work?
Has a stationary phase that remains in the machine and a moble phase that carries the inserted sample at different rates out of the machine, compounds are detected as they exit and produce and electrical current that is read to make a peak on the graph
How can you tell if two compounds are the same using GC?
If they have the same retention time
Why do some molecules travel through GC at a faster rate?
More volatile, they are not as strongly bonded with stationary phase
Explain how to isolate the samples of the mixture using acid base extraction. Note what compounds were used.
%5 NaOH used to extract carboxylic acid into water soluble salt into the aqueous phase, base and neutral remains in organic. 5% HCL is used to remove the amine and turn it into a salt from organic phase and into aqueous phase, leaving neutral in organic. Neutral is extracted from hot plate.
6 M HCL added to carboxylic salt to form a solid and then cooled. 6M NaOH to the amine salt to form a solid. Suction filtration to collect solid.
What was the purpose of cooling and using the litmus paper in the Separation?
Cooling the sample slowed down the particles in solution, decreasing solubility and the litmus paper was used to make sure the solutions were acidic and basic
Where does Polarization and intermolecular forces come into play with separation?
Polarization-caused the polar (aqueous) layer to form on the bottom and nonpolar (organic) layer to form on the stop to be separated using funnel
Intermolecular forces- formed to solid when the water did not want to interact with the nonpolar acid/base
How was the purification of the separated Acid/Base/Neutral done
They were recrystallized by heating the sample and the solvent in a water filled beaker on a hot plate. Solvent is slowly added until sample is dissolved. Let recrystallize. Melting point and FTIR is used to distinguish between possibilities
