Simple and Fractional Distillation

Benzene and cyclohexane are both flammable liquids. They are able to mix with each other without separating into two layers. They have very similar boiling points. It is difficult to separate a mixture of these two liquids by fractional distillation.

Why is it difficult to separate a mixture of benzene and cyclohexane by fractional distillation?

• They are both flammable.

• They have very similar boiling points.

• They are both liquids.

• They mix with each other completely.

What can be deduced from the result of this experiment?

• Ethanol has a higher boiling point than water.

• Ethanol has a lower melting point than water.

• Ethanol has a higher melting point than water.

• Ethanol has a lower boiling point than water.

State the general name for this method of mixture separation.

Predict the reading on the thermometer during the separation. _______ °C.

A mixture of ethanol (b.p. 78 ^oC) and water (b.p. 100 ^oC) are separated using fractional distillation. Identify the distillate that is first collected.

(Also think about why you made this guess)

• ethanol

• water

The liquid with the _______ boiling point distills first.

• higher

• lower

A mixture of ethanol (b.p. 78 ^oC) and water (b.p. 100 ^oC) are separated using fractional distillation.

When the mixture first boils, what is present near the bottom of the fractionating column?

• only ethanol

• only water

• mixture of equal percentage of ethanol and water

• mixture with higher percentage of ethanol

• mixture with higher percentage of water

Which part of the fractionating column is hotter?

• the bottom

• the top

As the mixture of ethanol (b.p. 78 ^oC) and water (b.p. 100 ^oC) rises through the fractionating column, what condenses back into a liquid?

• ethanol

• water

A mixture of ethanol (b.p. 78 ^oC) and water (b.p. 100 ^oC) are separated using fractional distillation.

When the mixture boils, what is at the top of the fractionating column?

• only ethanol

• only water

• mixture of equal percentage of methanol and water

• mixture with higher percentage of ethanol

• mixture with higher percentage of water