CHEM 103 LAB EXPERIMENTS 1–8 PRACTICE
QUESTIONS AND LAB RATIONALE GUIDE 2026
◉ In case of minor accidents which may require medical treatment,
we must always call which number? Answer: 747-5611 (Univ.
Police)
◉ Which item is missing from our lab? A copy of the Safety
Agreement is linked on the Laboratory Safety folder in 2125 Content
menu option. Answer: Fire Blanket
◉ It is only necessary to read the experimental section of the
textbook and not the full chapter for background information.
Answer: False
◉ You spilled some benzoic acid and need to dispose it. Where is it
disposed? Answer: Solid Waste container
◉ Some unused benzaldehyde from your laboratory experiment.
Where is it disposed? Answer: Non-halogenated waste
◉ Saturated sodium bicarbonate aqueous solution portion after a
liquid-liquid extraction. Where is it disposed? Answer: Aqueous
waste
,◉ Some unused dichloromethane from your laboratory experiment.
Where is it disposed? Answer: Halogenated waste container
◉ The major purification technique that we will learn in
Benzaldehyde experiment will be? Answer: Vacuum distillation
◉ Benzaldehyde experiment: the compound that is to be purified
Answer: Benzaldehyde
◉ Benzaldehyde experiment: the major contaminant of the
compound that is to be purified Answer: Benzoic Acid
◉ Benzaldehyde experiment: used to convert the major contaminant
to a salt that is more soluable in water Answer: %10 (g/v) aqueous
sodium carbonate
◉ Benzaldehyde experiment: used to remove excess base Answer:
Water
◉ Benzaldehyde experiment: used to remove water Answer:
anhydrrous magnesium sulfate
,◉ Benzaldehyde experiment: used to prevent the product from
oxidizing easily Answer: hydroquininone
◉ According to the text, how many mL of the starting material will
be used in Benzaldehyde experiment? Answer: 15
◉ Benzaldehyde Experiment: The product of each reaction should
be: Answer: Labeled and stored for use in subsequent reactions
◉ The boiling point of this final product of Benzaldehyde
experiment should be: Answer: Below 180 degrees
◉ The night after the vacuum distillation experiment, many
condensers start forming a white solid inside them. What is this
white solid? Answer: Benzoic acid
◉ As you observed, benzaldehyde is immiscible in water. Looking up
the density of benzaldehyde, match each condition to what you were
most likely to observe in "washing" benzaldehyde with different
liquids. Answer: washing with too little deionized water - an
emulsion
washing with plenty of deionized water - water floating on
benzaldehyde
washing with 10 % sodium carbonate - benzaldehyde floating on
water
, ◉ Given that:
0 °C = 273.15 °K,
Hvap(benzaldehyde) = 45.9 kj/mol,
benzaldehyde boils at 180 °C at 1 atm (760 mm Hg or torr),
and that the ideal gas constant is 8.3144621 j/°K mol;
at what temperature in °C should benzaldehyde distill if your
vacuum pressure is 82 mm Hg?
Provide 2 significant digits in your answers, for instance, 559 should
be rounded to 560. Answer: 110
◉ How many mL are required to get 13 g of a liquid with density
1.26? Give 2 significant digits in your answer. Answer: 10
◉ What is the percent recovery if you started with 9.3 mL of
benzaldehyde and ended with 4.1 g of benzaldehyde after
distillation? Give 2 significant figures in your answer. Assume the
density of benzaldehyde is 1.044. Answer: 42
◉ Given that:
QUESTIONS AND LAB RATIONALE GUIDE 2026
◉ In case of minor accidents which may require medical treatment,
we must always call which number? Answer: 747-5611 (Univ.
Police)
◉ Which item is missing from our lab? A copy of the Safety
Agreement is linked on the Laboratory Safety folder in 2125 Content
menu option. Answer: Fire Blanket
◉ It is only necessary to read the experimental section of the
textbook and not the full chapter for background information.
Answer: False
◉ You spilled some benzoic acid and need to dispose it. Where is it
disposed? Answer: Solid Waste container
◉ Some unused benzaldehyde from your laboratory experiment.
Where is it disposed? Answer: Non-halogenated waste
◉ Saturated sodium bicarbonate aqueous solution portion after a
liquid-liquid extraction. Where is it disposed? Answer: Aqueous
waste
,◉ Some unused dichloromethane from your laboratory experiment.
Where is it disposed? Answer: Halogenated waste container
◉ The major purification technique that we will learn in
Benzaldehyde experiment will be? Answer: Vacuum distillation
◉ Benzaldehyde experiment: the compound that is to be purified
Answer: Benzaldehyde
◉ Benzaldehyde experiment: the major contaminant of the
compound that is to be purified Answer: Benzoic Acid
◉ Benzaldehyde experiment: used to convert the major contaminant
to a salt that is more soluable in water Answer: %10 (g/v) aqueous
sodium carbonate
◉ Benzaldehyde experiment: used to remove excess base Answer:
Water
◉ Benzaldehyde experiment: used to remove water Answer:
anhydrrous magnesium sulfate
,◉ Benzaldehyde experiment: used to prevent the product from
oxidizing easily Answer: hydroquininone
◉ According to the text, how many mL of the starting material will
be used in Benzaldehyde experiment? Answer: 15
◉ Benzaldehyde Experiment: The product of each reaction should
be: Answer: Labeled and stored for use in subsequent reactions
◉ The boiling point of this final product of Benzaldehyde
experiment should be: Answer: Below 180 degrees
◉ The night after the vacuum distillation experiment, many
condensers start forming a white solid inside them. What is this
white solid? Answer: Benzoic acid
◉ As you observed, benzaldehyde is immiscible in water. Looking up
the density of benzaldehyde, match each condition to what you were
most likely to observe in "washing" benzaldehyde with different
liquids. Answer: washing with too little deionized water - an
emulsion
washing with plenty of deionized water - water floating on
benzaldehyde
washing with 10 % sodium carbonate - benzaldehyde floating on
water
, ◉ Given that:
0 °C = 273.15 °K,
Hvap(benzaldehyde) = 45.9 kj/mol,
benzaldehyde boils at 180 °C at 1 atm (760 mm Hg or torr),
and that the ideal gas constant is 8.3144621 j/°K mol;
at what temperature in °C should benzaldehyde distill if your
vacuum pressure is 82 mm Hg?
Provide 2 significant digits in your answers, for instance, 559 should
be rounded to 560. Answer: 110
◉ How many mL are required to get 13 g of a liquid with density
1.26? Give 2 significant digits in your answer. Answer: 10
◉ What is the percent recovery if you started with 9.3 mL of
benzaldehyde and ended with 4.1 g of benzaldehyde after
distillation? Give 2 significant figures in your answer. Assume the
density of benzaldehyde is 1.044. Answer: 42
◉ Given that:
