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Organic Chemistry 234 Lab Quiz
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- BCH 462 Urea Cycle, Fatty Acid Synthesis
Organic Chemistry 234 Lab Quiz
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Organic Chemistry 234 Lab QuizWhat is the proper thing to do shall your clothing catch on fire in the lab? -
CORRECT ANSWER-Use the safety shower
What is the appropriate way to put out a fire caused by an organic solvent? Why
is water not a good choice? - CORRECT ANSWER-Use the fire extinguisher
"ABC", water is not a good choice because some flammable materials react
violently with water and could make it worse.
What should you do when chemicals get in your eye? - CORRECT
ANSWER-Remove your contacts/wash your eyes out at eyewash station for 15
mins
What should you do when chemicals get on your skin? - CORRECT
ANSWER-Immediately wash your skin for 15 mins, use safety shower or faucet
depending on size
Why is water not a good choice? - CORRECT ANSWER-Water is not a good
choice because some flammable materials react violently with water and could
make it worse
Why should a hot plate not be used to heat organic solvents? - CORRECT
ANSWER-Hot plates are able to reach very high temperatures which are hot
enough to ignite low boiling solvents.
Why should Bunsen burner be avoided in an organic lab? - CORRECT
ANSWER-Many organic compounds are flammable so heating them with a
Bunsen burner could ignite the compound and cause a fire or explosion.
How should you respond if you spill acid or base on your skin? - CORRECT
ANSWER-Immediately wash with water.
What defines the difference between non-halogenated and halogenated organic
wastes? - CORRECT ANSWER-A non-halogenated compound doesn't have a
halogen attached to it (Iodine, Chlorine, Bromine, Fluorine)
,A halogenated compound does have a halogen attached to it
Organic compounds are commonly hazardous. What make them inherent
hazardous in the lab? - CORRECT ANSWER-They can be flammable/toxic.
Why must glass waste (e.g. capillary tubes, broken beakers) not be disposed into
a regular trash container? - CORRECT ANSWER-It can rip through bag and hurt
the person handling it.
What functional groups are considered hydrophilic? - CORRECT
ANSWER-Carboxylic acids and Hydroxyl
What functional groups are considered hydrophobic? - CORRECT
ANSWER-Aromatic rings and Ether
What determines the solubility of an organic compound in water? - CORRECT
ANSWER-The polarity of a substance (more polar = more solubility)
What is the difference between a solid melting and a solid dissolving in a
solvent? - CORRECT ANSWER-When a solid melts, heat is added.
Solvent is added to a solid sample to turn into a dissolved sample.
What quantitative physical property is a good measurement for solvent polarity? -
CORRECT ANSWER-The dielectric constant (higher constant = stronger
polarity)
What is the difference between bond polarity vs. molecular polarity? - CORRECT
ANSWER-Molecular polarity is the polarity of the whole covalent molecule
Bond polarity is the polarity of a covalent bond
How does the composition of organic structure (e.g. increase in carbon length,
number of OH's, NH's) affect its polarity? - CORRECT ANSWER-As the chemical
structure has more carbon chain surface area, the solubility decreases. (more
carbons and less OH groups = insoluble). More carbons = less polar. When there
are four carbons per OH, the molecules will be soluble in H2O.
, What is an extraction? - CORRECT ANSWER-A separation of compounds by
filtration
What does a liquid-liquid extraction involve (e.g. number of solvents and
choices)? - CORRECT ANSWER-Can be between two liquids (two solvents) or
between liquid and solid (one solvent)
How does a liquid-liquid extraction work? - CORRECT ANSWER-A separatory
funnel is used to perform vacuum filtration to separate immiscible liquids
How many layers are usually involved? - CORRECT ANSWER-Two layers are
involved
What determines which layer is the bottom or top layer in a separatory funnel? -
CORRECT ANSWER-Density determines which layer is on top or bottom (more
dense = bottom layer)
Benzoic acid does not dissolve in cold water but dissolves in dilute aqueous
NaOH. Why? - CORRECT ANSWER-Since "like dissolves like", benzoic acid
doesn't dissolve in water because water is polar and benzoic acid is non polar.
Additionally, benzoic acid is a weak acid, therefore it can only partially dissolve in
water. It dissolves in dilute aqueous NaOH because NaOH is a strong base, it will
attack the weak acid to form a salt.
What is a separatory funnel used for during an extraction? - CORRECT
ANSWER-Separatory funnel is used to separate immiscible liquids.
Why should it be inverted and vented often after two solvents mixed in a
separatory funnel are shaken? - CORRECT ANSWER-It should be inverted and
vented often after two solvents are mixed in a separatory funnel and the funnel is
shaken so that it released the pressure. This is necessary because if this isn't
done, the pressure build-up might push the stopper out of the compound which
would result in losing the compound.
What is the purpose of a recrystallization? - CORRECT ANSWER-To purify
solids.
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