CHM 206 LAB FINAL COMPLETE EXAM QUESTIONS AND ANSWERS TO
HELP YOU PASS
Q1. What is the primary purpose of wearing safety goggles in the lab?
A1. To protect eyes from chemical splashes, broken glassware, and harmful
vapors.
Q2. Why should long hair be tied back in the laboratory?
A2. To prevent it from catching fire or coming into contact with chemicals or
equipment.
Q3. What should you do immediately if you spill acid on your skin?
A3. Rinse the affected area with copious amounts of water for at least 15 minutes
and notify the instructor.
Q4. What is a fume hood and when should it be used?
A4. A fume hood is a ventilated enclosure used when working with volatile, toxic,
or noxious chemicals to prevent inhalation of harmful vapors.
Q5. Why is it important to read the MSDS (Material Safety Data Sheet)
before handling chemicals?
A5. The MSDS provides important information about chemical hazards, proper
handling procedures, and emergency response measures.
Q6. What does 'dilute acids into water, never water into acid' mean?
A6. Always add concentrated acid slowly to water to dissipate heat safely; adding
water to acid can cause violent splattering due to rapid heat generation.
Q7. What is the proper way to smell a chemical in the laboratory?
A7. Use the wafting technique: gently wave your hand over the container toward
your nose rather than directly inhaling.
Q8. Why should you never pipette by mouth?
A8. Mouth pipetting can lead to accidental ingestion or inhalation of hazardous
chemicals.
,Q9. What is the first step in case of a fire in the laboratory?
A9. Alert others, activate the fire alarm if necessary, and use appropriate fire
extinguisher if the fire is small and contained, or evacuate if it's large.
Q10. What type of fire extinguisher should be used for organic solvent fires?
A10. Class B fire extinguisher (for flammable liquids) or ABC multipurpose
extinguisher.
Q11. Why should you never heat a closed system?
A11. Heating a closed system can cause pressure buildup leading to explosion.
Q12. What is the proper technique for inserting glass tubing into a rubber
stopper?
A12. Lubricate the glass and stopper with water or glycerin, protect hands with a
towel, and use gentle twisting motion.
Q13. What does NFPA diamond rating system indicate?
A13. It indicates health hazards (blue), flammability (red), reactivity (yellow), and
special hazards (white) on a scale of 0-4.
Q14. Why should organic waste and aqueous waste be disposed of separately?
A14. They have different chemical properties and disposal methods; mixing can
cause dangerous reactions or environmental contamination.
Q15. What is the function of a desiccator?
A15. A desiccator maintains a moisture-free environment for storing hygroscopic
substances or drying samples.
Q16. Why is it important to check glassware for cracks before use?
A16. Cracked glassware can break during heating or under vacuum, causing
chemical spills or injury.
Q17. What is the proper procedure for diluting concentrated sulfuric acid?
A17. Add acid slowly to water with constant stirring, never the reverse, to prevent
violent exothermic reaction.
Q18. What should you do if a chemical gets in your eye?
A18. Immediately use the eyewash station to rinse for at least 15 minutes while
holding eyelids open, then seek medical attention.
,Q19. Why should you never use chipped or cracked beakers for heating?
A19. They are structurally weak and may shatter when heated, causing chemical
spills and potential injury.
Q20. What is the purpose of a safety shower?
A20. To quickly rinse off large chemical spills on the body or clothing, or to
extinguish clothing fires.
Q21. What does GHS stand for and what is its purpose?
A21. Globally Harmonized System of Classification and Labeling of Chemicals; it
standardizes chemical hazard communication worldwide.
Q22. Why should food and drinks never be brought into the laboratory?
A22. They can become contaminated with harmful chemicals and lead to
accidental ingestion.
Q23. What is the proper way to heat a test tube?
A23. Hold at an angle using a test tube holder, heat gently while moving over the
flame, and point opening away from yourself and others.
Q24. What does a yellow flame on a Bunsen burner indicate?
A24. Incomplete combustion due to insufficient air; adjust the air intake to get a
blue flame for efficient heating.
Q25. Why must you never leave a heating mantle or hot plate unattended?
A25. To prevent overheating, fires, or damage to equipment and experiments.
Q26. What is the purpose of using boiling chips?
A26. To provide nucleation sites for even bubble formation and prevent bumping
or superheating of liquids.
Q27. Why should you add reagents slowly in many organic reactions?
A27. To control the rate of reaction, prevent overheating, and avoid violent
reactions or splashing.
Q28. What is proper protocol if you break a mercury thermometer?
A28. Evacuate the area, notify the instructor immediately, and do not attempt to
clean it up yourself as mercury is toxic.
, Q29. Why should sharps (needles, broken glass) be disposed of in designated
containers?
A29. To prevent injury to laboratory personnel and custodial staff, and to allow
proper disposal.
Q30. What information must be on a chemical label?
A30. Chemical name, concentration, date prepared, preparer's name, and
appropriate hazard warnings.
HELP YOU PASS
Q1. What is the primary purpose of wearing safety goggles in the lab?
A1. To protect eyes from chemical splashes, broken glassware, and harmful
vapors.
Q2. Why should long hair be tied back in the laboratory?
A2. To prevent it from catching fire or coming into contact with chemicals or
equipment.
Q3. What should you do immediately if you spill acid on your skin?
A3. Rinse the affected area with copious amounts of water for at least 15 minutes
and notify the instructor.
Q4. What is a fume hood and when should it be used?
A4. A fume hood is a ventilated enclosure used when working with volatile, toxic,
or noxious chemicals to prevent inhalation of harmful vapors.
Q5. Why is it important to read the MSDS (Material Safety Data Sheet)
before handling chemicals?
A5. The MSDS provides important information about chemical hazards, proper
handling procedures, and emergency response measures.
Q6. What does 'dilute acids into water, never water into acid' mean?
A6. Always add concentrated acid slowly to water to dissipate heat safely; adding
water to acid can cause violent splattering due to rapid heat generation.
Q7. What is the proper way to smell a chemical in the laboratory?
A7. Use the wafting technique: gently wave your hand over the container toward
your nose rather than directly inhaling.
Q8. Why should you never pipette by mouth?
A8. Mouth pipetting can lead to accidental ingestion or inhalation of hazardous
chemicals.
,Q9. What is the first step in case of a fire in the laboratory?
A9. Alert others, activate the fire alarm if necessary, and use appropriate fire
extinguisher if the fire is small and contained, or evacuate if it's large.
Q10. What type of fire extinguisher should be used for organic solvent fires?
A10. Class B fire extinguisher (for flammable liquids) or ABC multipurpose
extinguisher.
Q11. Why should you never heat a closed system?
A11. Heating a closed system can cause pressure buildup leading to explosion.
Q12. What is the proper technique for inserting glass tubing into a rubber
stopper?
A12. Lubricate the glass and stopper with water or glycerin, protect hands with a
towel, and use gentle twisting motion.
Q13. What does NFPA diamond rating system indicate?
A13. It indicates health hazards (blue), flammability (red), reactivity (yellow), and
special hazards (white) on a scale of 0-4.
Q14. Why should organic waste and aqueous waste be disposed of separately?
A14. They have different chemical properties and disposal methods; mixing can
cause dangerous reactions or environmental contamination.
Q15. What is the function of a desiccator?
A15. A desiccator maintains a moisture-free environment for storing hygroscopic
substances or drying samples.
Q16. Why is it important to check glassware for cracks before use?
A16. Cracked glassware can break during heating or under vacuum, causing
chemical spills or injury.
Q17. What is the proper procedure for diluting concentrated sulfuric acid?
A17. Add acid slowly to water with constant stirring, never the reverse, to prevent
violent exothermic reaction.
Q18. What should you do if a chemical gets in your eye?
A18. Immediately use the eyewash station to rinse for at least 15 minutes while
holding eyelids open, then seek medical attention.
,Q19. Why should you never use chipped or cracked beakers for heating?
A19. They are structurally weak and may shatter when heated, causing chemical
spills and potential injury.
Q20. What is the purpose of a safety shower?
A20. To quickly rinse off large chemical spills on the body or clothing, or to
extinguish clothing fires.
Q21. What does GHS stand for and what is its purpose?
A21. Globally Harmonized System of Classification and Labeling of Chemicals; it
standardizes chemical hazard communication worldwide.
Q22. Why should food and drinks never be brought into the laboratory?
A22. They can become contaminated with harmful chemicals and lead to
accidental ingestion.
Q23. What is the proper way to heat a test tube?
A23. Hold at an angle using a test tube holder, heat gently while moving over the
flame, and point opening away from yourself and others.
Q24. What does a yellow flame on a Bunsen burner indicate?
A24. Incomplete combustion due to insufficient air; adjust the air intake to get a
blue flame for efficient heating.
Q25. Why must you never leave a heating mantle or hot plate unattended?
A25. To prevent overheating, fires, or damage to equipment and experiments.
Q26. What is the purpose of using boiling chips?
A26. To provide nucleation sites for even bubble formation and prevent bumping
or superheating of liquids.
Q27. Why should you add reagents slowly in many organic reactions?
A27. To control the rate of reaction, prevent overheating, and avoid violent
reactions or splashing.
Q28. What is proper protocol if you break a mercury thermometer?
A28. Evacuate the area, notify the instructor immediately, and do not attempt to
clean it up yourself as mercury is toxic.
, Q29. Why should sharps (needles, broken glass) be disposed of in designated
containers?
A29. To prevent injury to laboratory personnel and custodial staff, and to allow
proper disposal.
Q30. What information must be on a chemical label?
A30. Chemical name, concentration, date prepared, preparer's name, and
appropriate hazard warnings.
