Chem 120L exam Questions and
Answers
Goggles must be worn because: - ---User inexperience increases the chance
of splashes and chemical spills
--The number of students working in the lab increases the chances of
collision and subsequently chemical splashes
--They provide protection from flying objects such as broken shards of glass
--They provide maximum protection from chemicals spilled or splashed in the
eyes
- To maintain a safe working environment in the laboratory it is important
for each student to: - -Become familiar with the safe handling procedures for
each chemical used
Clean up all spills as soon as they occur
Learn the location of all safety equipment in the lab room
Keep aisles between benches free of trip hazards such as knapsacks or
unused stools
- Liquid dripping down the sides of a bottles poses a safety hazard because:
- -It leaves "bottle ring" spills which could damage or react with the bench
surface
It makes the bottle slippery and increases the chances of dropping it
It could be dangerous for the next user to touch
- Fire safety in the First Year Chemistry lab requires that each student learn
the location of: - -The nearest fire alarm pull station
The nearest fire extinguisher
The fire exit route from the room and building
- Which of the following precautions should be taken to ensure that all of the
initial copper is recovered? - -Avoid spilling solutions during transfer
Stir continuously when boiling to avoid bumping
Solid products adhering to beakers should be added into the next solution
- When using vacuum filtration to separate a solid product from a liquid,
what is the maximum depth of solution that should be added to the Buchner
funnel? - -two-thirds of the depth of the funnel
, - In the technique of vacuum filtration, what is the "filtrate"? - -the liquid
that is drawn into the flask
- what is bumping? - -The formation and subsequent bursting of large air
bubbles trapped under a layer of solid precipitate in solution
- What does it mean to "decant the solution"? - -to pour off a liquid to
separate it from a solid precipitate
- What does it mean to "quantitatively transfer"? - -To move all material
from one location to another with no loss of material
- What is a supernatant? - -The liquid overlying a precipitated solid
- In the technique of analytical weighing by difference the receiving flasks
used need to be clean, but do not need to be _____ - -dry
- The advantages of using the technique of analytical weighing by difference
are: - -only n+1 weighings are required to prepare n samples
the balance does not need to be zeroed between weighings
the receiving flasks do not need to be dry
- A glass funnel should not be used when filling the burette with solution,
why? - -Only plastic funnels should be used when filling burettes. Funnels
tend to wobble back and forth in a burette, this movement causes the funnel
stem to break off ($12 replacement fee) or the top of the burette to crack
and break ($40 replacement fee!).
- T or F? Air bubbles must be removed from the tip of the burette before
beginning a titration. - -True
- To quantitatively transfer a solution or solid simply means: - -that all
solution or solid is transferred from one place to another
- An acid that is diprotic must have: - -two titratable acidic protons
- In chemistry, a solution that has been standardized has: - -an accurately
determined concentration
- What is the definition of a titrant solution used in titrations? - -the liquid
dispensed from the burette
- The indicator phenolphthalein is a weak organic acid whose unprotonated
form is: - -pink / red
Answers
Goggles must be worn because: - ---User inexperience increases the chance
of splashes and chemical spills
--The number of students working in the lab increases the chances of
collision and subsequently chemical splashes
--They provide protection from flying objects such as broken shards of glass
--They provide maximum protection from chemicals spilled or splashed in the
eyes
- To maintain a safe working environment in the laboratory it is important
for each student to: - -Become familiar with the safe handling procedures for
each chemical used
Clean up all spills as soon as they occur
Learn the location of all safety equipment in the lab room
Keep aisles between benches free of trip hazards such as knapsacks or
unused stools
- Liquid dripping down the sides of a bottles poses a safety hazard because:
- -It leaves "bottle ring" spills which could damage or react with the bench
surface
It makes the bottle slippery and increases the chances of dropping it
It could be dangerous for the next user to touch
- Fire safety in the First Year Chemistry lab requires that each student learn
the location of: - -The nearest fire alarm pull station
The nearest fire extinguisher
The fire exit route from the room and building
- Which of the following precautions should be taken to ensure that all of the
initial copper is recovered? - -Avoid spilling solutions during transfer
Stir continuously when boiling to avoid bumping
Solid products adhering to beakers should be added into the next solution
- When using vacuum filtration to separate a solid product from a liquid,
what is the maximum depth of solution that should be added to the Buchner
funnel? - -two-thirds of the depth of the funnel
, - In the technique of vacuum filtration, what is the "filtrate"? - -the liquid
that is drawn into the flask
- what is bumping? - -The formation and subsequent bursting of large air
bubbles trapped under a layer of solid precipitate in solution
- What does it mean to "decant the solution"? - -to pour off a liquid to
separate it from a solid precipitate
- What does it mean to "quantitatively transfer"? - -To move all material
from one location to another with no loss of material
- What is a supernatant? - -The liquid overlying a precipitated solid
- In the technique of analytical weighing by difference the receiving flasks
used need to be clean, but do not need to be _____ - -dry
- The advantages of using the technique of analytical weighing by difference
are: - -only n+1 weighings are required to prepare n samples
the balance does not need to be zeroed between weighings
the receiving flasks do not need to be dry
- A glass funnel should not be used when filling the burette with solution,
why? - -Only plastic funnels should be used when filling burettes. Funnels
tend to wobble back and forth in a burette, this movement causes the funnel
stem to break off ($12 replacement fee) or the top of the burette to crack
and break ($40 replacement fee!).
- T or F? Air bubbles must be removed from the tip of the burette before
beginning a titration. - -True
- To quantitatively transfer a solution or solid simply means: - -that all
solution or solid is transferred from one place to another
- An acid that is diprotic must have: - -two titratable acidic protons
- In chemistry, a solution that has been standardized has: - -an accurately
determined concentration
- What is the definition of a titrant solution used in titrations? - -the liquid
dispensed from the burette
- The indicator phenolphthalein is a weak organic acid whose unprotonated
form is: - -pink / red
