CHEM 123 Lab Final UBC — 100 Practice
Questions with Answers
Section 1: Laboratory Techniques & Equipment
(Q1–25)
1. Why do we perform iodometric titrations?
A) To measure pH
B) To find the concentration of an unknown by mixing it with a solution of known
concentration
C) To determine boiling point
D) To separate mixtures
Answer: B
2. What are the four general steps of an iodometric titration?
A) Measure, mix, heat, cool
B) Combine solutions, reach endpoint, calculate, determine concentration of unknown
C) Weigh, dissolve, filter, evaporate
D) Pipette, dilute, shake, read
Answer: B
3. What reaction takes place during an iodometric titration?
A) Acid-base neutralization
B) Precipitation
C) Oxidation-reduction reaction
D) Complexation
Answer: C
4. What is used as the oxidizing agent in an iodometric titration?
A) Sodium thiosulfate
B) Potassium iodate
C) Starch
D) Hydrochloric acid
Answer: B
5. A top-loading balance obtains mass to the nearest:
A) ±0.0001 g
B) ±0.001 g
,C) ±0.05 g
D) ±0.5 g
Answer: C (±0.1 g with uncertainty of ±0.05 g)
6. An analytical balance obtains mass to the nearest:
A) ±0.1 g
B) ±0.01 g
C) ±0.001 g
D) ±0.0001 g
Answer: D
7. Which balance measurement must be recorded to 4 decimal places?
A) Top-loading balance
B) Analytical balance
C) Both
D) Neither
Answer: B
8. When is a balance reading considered stable?
A) Persists for 1 second
B) Persists for 2 seconds
C) Persists for 5 seconds
D) Persists for 10 seconds
Answer: B
9. At what temperature should objects be weighed?
A) Any temperature
B) Room temperature
C) As cold as possible
D) As hot as possible
Answer: B (to avoid convection currents)
10. Should objects be dry or wet when weighed?
A) Wet
B) Dry
C) Either
D) Slightly damp
Answer: B
11. What is a parallax error?
A) Equipment is dirty
, B) Reading is taken at wrong angle
C) Liquid is hot
D) Instrument is broken
Answer: B (eye level higher or lower than meniscus)
12. Which glassware provides the most accurate volume measurement?
A) Beaker
B) Erlenmeyer flask
C) Graduated cylinder
D) Volumetric flask
Answer: D
13. What is the primary purpose of a fume hood?
A) Increase reaction rate
B) Protect from chemical vapors
C) Store chemicals
D) Measure gases
Answer: B
14. Which PPE is always required in the chemistry lab?
A) Gloves only
B) Goggles only
C) Lab coat, goggles, and appropriate clothing
D) Mask only
Answer: C
15. If a strong acid spills on your skin, the first action is:
A) Apply neutralizing agent immediately
B) Rinse with plenty of water for 15 minutes
C) Wipe with paper towel
D) Go to hospital directly
Answer: B
16. What should you never do when pipetting?
A) Use a pipette bulb
B) Pipette by mouth
C) Rinse with sample
D) Hold at eye level
Answer: B
Questions with Answers
Section 1: Laboratory Techniques & Equipment
(Q1–25)
1. Why do we perform iodometric titrations?
A) To measure pH
B) To find the concentration of an unknown by mixing it with a solution of known
concentration
C) To determine boiling point
D) To separate mixtures
Answer: B
2. What are the four general steps of an iodometric titration?
A) Measure, mix, heat, cool
B) Combine solutions, reach endpoint, calculate, determine concentration of unknown
C) Weigh, dissolve, filter, evaporate
D) Pipette, dilute, shake, read
Answer: B
3. What reaction takes place during an iodometric titration?
A) Acid-base neutralization
B) Precipitation
C) Oxidation-reduction reaction
D) Complexation
Answer: C
4. What is used as the oxidizing agent in an iodometric titration?
A) Sodium thiosulfate
B) Potassium iodate
C) Starch
D) Hydrochloric acid
Answer: B
5. A top-loading balance obtains mass to the nearest:
A) ±0.0001 g
B) ±0.001 g
,C) ±0.05 g
D) ±0.5 g
Answer: C (±0.1 g with uncertainty of ±0.05 g)
6. An analytical balance obtains mass to the nearest:
A) ±0.1 g
B) ±0.01 g
C) ±0.001 g
D) ±0.0001 g
Answer: D
7. Which balance measurement must be recorded to 4 decimal places?
A) Top-loading balance
B) Analytical balance
C) Both
D) Neither
Answer: B
8. When is a balance reading considered stable?
A) Persists for 1 second
B) Persists for 2 seconds
C) Persists for 5 seconds
D) Persists for 10 seconds
Answer: B
9. At what temperature should objects be weighed?
A) Any temperature
B) Room temperature
C) As cold as possible
D) As hot as possible
Answer: B (to avoid convection currents)
10. Should objects be dry or wet when weighed?
A) Wet
B) Dry
C) Either
D) Slightly damp
Answer: B
11. What is a parallax error?
A) Equipment is dirty
, B) Reading is taken at wrong angle
C) Liquid is hot
D) Instrument is broken
Answer: B (eye level higher or lower than meniscus)
12. Which glassware provides the most accurate volume measurement?
A) Beaker
B) Erlenmeyer flask
C) Graduated cylinder
D) Volumetric flask
Answer: D
13. What is the primary purpose of a fume hood?
A) Increase reaction rate
B) Protect from chemical vapors
C) Store chemicals
D) Measure gases
Answer: B
14. Which PPE is always required in the chemistry lab?
A) Gloves only
B) Goggles only
C) Lab coat, goggles, and appropriate clothing
D) Mask only
Answer: C
15. If a strong acid spills on your skin, the first action is:
A) Apply neutralizing agent immediately
B) Rinse with plenty of water for 15 minutes
C) Wipe with paper towel
D) Go to hospital directly
Answer: B
16. What should you never do when pipetting?
A) Use a pipette bulb
B) Pipette by mouth
C) Rinse with sample
D) Hold at eye level
Answer: B
