CHEM 123 FINAL EXAM ACTUAL EXAM 2026 | LAB
FINAL EXAM | ALL QUESTIONS AND CORRECT
ANSWERS | VERIFIED ANSWERS | UPDATED
VERSION
What is something you should never do when pipetting? ---------
CORRECT ANSWER-----------------never pipet from a reagent stock bottle
or volumetric flask (could contaminate stock solution/break neck of the
volumetric flask)
How to deliver solution from pipette ---------CORRECT ANSWER------------
------ quickly transfer the filled pipette to Erlenmeyer flask (keep index-
finger tightly over pipette to maintain suction)
- drain the pipette (touch tip to side of Erlenmeyer flask, release finger
and allow to drain by gravity & hold the pipette to the side of
Erlenmeyer flask for another 10 seconds)
**Do not blow/shake out small amount of solution remaining in the tip
of the pipette**
How to clean the burette ---------CORRECT ANSWER------------------ use
clean funnel over the sink & add 5-10mL of deionized water with the
stopcock closed
,- hold in horizontal position and roll to coat insides with water
- drain water through tip by opening the stopcock
- repeat 2x
- close stopcock again and use clean funnel & add 5-10mL of solution
into burette
- hold horizontally and coat sides of burette with solution & drain
through stopcock into sink or waste beaker
How to fill the burette ---------CORRECT ANSWER------------------ close
stopcock & use funnel to fill burette to 0 mark & clamp burette at
bench with waste beaker under the tip
- open stopcock to drain some solution to ensure the burette has no air
bubbles (not essential to fill exactly to 0.00)
- fill the burette, remove funnel, touch tip of burette to inside wall of a
beaker to remove any drops on the tip
How to read the burette ---------CORRECT ANSWER------------------ read at
lowest point of meniscus (make sure eyes are parallel)
- use white card/paper behind the burette below meniscus to see
- record meniscus/volume of burette to 2 decimal places
, How to Operate the burette ---------CORRECT ANSWER------------------
record initial volume of burette to 2 decimal places
- lower burette tip into erlenmeyer flask that has the solution to be
titrated
- open stopcock slowly with left hand & adjust flow rate by using thumb
& 2 fingers around the stopcock
- turn on magnetic stirrer to low speed (avoids solution splashing up
walls of the flask
- wait about 30 seconds & record final volume of the burette to 2
decimal places
Why do we perform iodometric titrations ---------CORRECT ANSWER------
-----------to find the concentration of an unknown by mixing it with a
solution of known concentration
What are the 4 (general) steps of an iodometric titration? ---------
CORRECT ANSWER-----------------combine solutions, reach endpoint,
calculate, determine the concentration of the unknown
What reaction takes place during an iodometric titration? ---------
CORRECT ANSWER-----------------oxidation-reduction reaction
FINAL EXAM | ALL QUESTIONS AND CORRECT
ANSWERS | VERIFIED ANSWERS | UPDATED
VERSION
What is something you should never do when pipetting? ---------
CORRECT ANSWER-----------------never pipet from a reagent stock bottle
or volumetric flask (could contaminate stock solution/break neck of the
volumetric flask)
How to deliver solution from pipette ---------CORRECT ANSWER------------
------ quickly transfer the filled pipette to Erlenmeyer flask (keep index-
finger tightly over pipette to maintain suction)
- drain the pipette (touch tip to side of Erlenmeyer flask, release finger
and allow to drain by gravity & hold the pipette to the side of
Erlenmeyer flask for another 10 seconds)
**Do not blow/shake out small amount of solution remaining in the tip
of the pipette**
How to clean the burette ---------CORRECT ANSWER------------------ use
clean funnel over the sink & add 5-10mL of deionized water with the
stopcock closed
,- hold in horizontal position and roll to coat insides with water
- drain water through tip by opening the stopcock
- repeat 2x
- close stopcock again and use clean funnel & add 5-10mL of solution
into burette
- hold horizontally and coat sides of burette with solution & drain
through stopcock into sink or waste beaker
How to fill the burette ---------CORRECT ANSWER------------------ close
stopcock & use funnel to fill burette to 0 mark & clamp burette at
bench with waste beaker under the tip
- open stopcock to drain some solution to ensure the burette has no air
bubbles (not essential to fill exactly to 0.00)
- fill the burette, remove funnel, touch tip of burette to inside wall of a
beaker to remove any drops on the tip
How to read the burette ---------CORRECT ANSWER------------------ read at
lowest point of meniscus (make sure eyes are parallel)
- use white card/paper behind the burette below meniscus to see
- record meniscus/volume of burette to 2 decimal places
, How to Operate the burette ---------CORRECT ANSWER------------------
record initial volume of burette to 2 decimal places
- lower burette tip into erlenmeyer flask that has the solution to be
titrated
- open stopcock slowly with left hand & adjust flow rate by using thumb
& 2 fingers around the stopcock
- turn on magnetic stirrer to low speed (avoids solution splashing up
walls of the flask
- wait about 30 seconds & record final volume of the burette to 2
decimal places
Why do we perform iodometric titrations ---------CORRECT ANSWER------
-----------to find the concentration of an unknown by mixing it with a
solution of known concentration
What are the 4 (general) steps of an iodometric titration? ---------
CORRECT ANSWER-----------------combine solutions, reach endpoint,
calculate, determine the concentration of the unknown
What reaction takes place during an iodometric titration? ---------
CORRECT ANSWER-----------------oxidation-reduction reaction
