Organic Chemistry Laboratory Quiz

Why is suction filtration (vacuum) preferred to gravity filtration in recrystallization?

• It reduces the risk of contamination

• It allows for better separation of impurities

• It is faster and more efficient

• It prevents loss of product due to evaporation

Explain the behavior of a small amount of benzoic acid remaining unmelted even at temperatures above 200oC during a melting point test.

• The benzoic acid has a high molecular weight

• The benzoic acid is a mixture of different compounds

• The benzoic acid has a polymorphic structure

• The impurities in the benzoic acid affect its melting point

What are the purposes of boiling stones and seed crystals in the recrystallization of solids?

• Boiling stones help maintain a constant temperature, while seed crystals initiate crystallization

• Boiling stones reduce impurities, while seed crystals improve yield

• Boiling stones prevent splattering, while seed crystals provide structural support

• Boiling stones increase solubility, while seed crystals enhance purity

Why can boiling chips not be reused in laboratory experiments?

• They lose their effectiveness after one use

• They degrade when exposed to high temperatures

• They become contaminated with impurities

• They may contain residual solvents

If 5.0 g of compound 'Y' were to be recrystallized from 75 ml acetone, what will be the maximum amount of 'Y' that will be recrystallized?

• 4.0 g

• 3.5 g

• 3.0 g

• 4.5 g

What is the purpose of determining melting points?

• To calculate density

• To identify unknown compounds

• To separate mixtures

• To measure volume

Why could the rate of heating influence the melting point?

• To increase pressure

• To slow down the experiment

• To speed up the experiment

• To avoid decomposition

What is the advantage of steam distillation when compared to simple distillation?

• Avoids decomposition

• Lower cost

• Faster process

• Higher temperature

How does salting out work?

• Accelerates reaction

• Decreases solubility

• Increases solubility

• Inhibits reaction

What are some uses of essential oils?

• Cooking

• Perfumes

• Cleaning

• Medicine