1|Page
Chem 123 Lab Final UBC Actual Exam Questions
And Answers Practice Questions with Solutions
Newest 2026-2027 | Already Graded A+
How to deliver solution from pipette - 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 - 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
,2|Page
- hold horizontally and coat sides of burette with solution &
drain through stopcock into sink or waste beaker
how to fill the burette - 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 - 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 - 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
, 3|Page
- 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
precision - ANSWER-how close measured values are to each
other
accuracy - ANSWER-how close a measured value is to the true
value
what does more significant figures mean? - ANSWER-means
that the measurement is more precise
what significant figures are certain and which are uncertain? -
ANSWER-all digits but the last one are certain
the last digit is uncertain
what is the general rule for volumetric analysis and sig figs? -
ANSWER-measurements need to be precise to at least 4 sig figs
Chem 123 Lab Final UBC Actual Exam Questions
And Answers Practice Questions with Solutions
Newest 2026-2027 | Already Graded A+
How to deliver solution from pipette - 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 - 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
,2|Page
- hold horizontally and coat sides of burette with solution &
drain through stopcock into sink or waste beaker
how to fill the burette - 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 - 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 - 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
, 3|Page
- 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
precision - ANSWER-how close measured values are to each
other
accuracy - ANSWER-how close a measured value is to the true
value
what does more significant figures mean? - ANSWER-means
that the measurement is more precise
what significant figures are certain and which are uncertain? -
ANSWER-all digits but the last one are certain
the last digit is uncertain
what is the general rule for volumetric analysis and sig figs? -
ANSWER-measurements need to be precise to at least 4 sig figs
