Crowdly

avoid getting fingerprints or dirt on the clear faces

do not overfill the cuvette

When using a spectrophotometer, when do you press the 'auto-zero' button?

before measuring each absorbance

only once - when a cuvette filled with water is in the spectrophotometer

never - the spectrophotometer sets the zero absorbance automatically

Why must the conical flask used for the reaction between the salicylic acid and acetic anhydride be dry?

water will react with salicylic acid

water will react with sulfuric acid

water will shift the equilibrium, producing less aspirin

water will react with acetic anhydride

Which of the chemicals used in this experiment is the most hazardous, requiring long-cuff gloves for its safe handling?

Fe³⁺ dissolved in ethanol

sulfuric acid

acetic anhydride

ethanol

salicylic acid

In order to carry out a vacuum filtration, what equipment do you need? Tick all items that are required, but do no tick any non-essential items.

Rubber square with hole.

Small circular filter paper.

Regular test tube.

Rubber tubing from a bunsen burner.

Hirsch funnel.

Thick-walled rubber tube.

Side-arm test tube.

0.0181 mol salicylic acid; 0.0196 mol acetic anhydride

A student carrying out the aspirin synthesis as described in the lab manual started with 1.94 g of salicylic acid and reacted it with 2.5 mL of acetic anhydride (density = 1.082 g/mL) and 5 drops of 18 M sulfuric acid. What is their expected (theoretical) yield of aspirin?

A student carrying out the aspirin synthesis as described in the lab manual started with 1.85 g of salicylic acid and reacted it with 2.50 mL of acetic anhydride (density = 1.082 g/mL) and 5 drops of 18 M sulfuric acid. What are the amounts of salicylic acid and acetic anhydride reacting?

0.0147 mol salicylic acid; 0.0265 mol acetic anhydride

0.0134 mol salicylic acid; 0.0265 mol acetic anhydride

100%

How is the purity of the aspirin assessed in this experiment?

from its solubility

from the colour produced by reaction with Fe³⁺

by NMR spectroscopy