Fractional Distillation Concepts

What process is taking place at A?

• Evaporation

• Condensation

• Precipitation

• Transpiration

Vapour rises up the fractional distillation column, is the column cooler or hotter at the top?

• Cooler

• Hotter

• The same temperature

• Variable temperature

What do hydrocarbons in each fraction have in common?

• Number of carbon atoms and boiling point

• Molecular weight and density

• Color and odor

• Solubility in water and viscosity

Where do Smaller fractions condense?

• Higher up the column.

• At the bottom of the column.

• In the middle of the column.

• Outside the column.

Long-chain hydrocarbons have higher boiling points due to....?

• They have weaker intermolecular forces, so less energy is needed to overcome them.

• They have stronger intermolecular forces, so more energy is needed to overcome them.

• They have lower molecular weights, which reduces boiling points.

• They are more branched, leading to lower boiling points.

General formula for alkanes.

• C_nH_{2n}

• C_nH_{2n+1}

• C_nH_{2n+2}

• C_nH_{2n-2}

Changes of state in distillation

• Evaporation and condensation

• Sublimation and deposition

• Melting and freezing

• Ionization and recombination

The method used to separate the different hydrocarbons in crude oil

• Fractional distillation

• Simple distillation

• Filtration

• Chromatography

The property of hydrocarbons used to separate them using fractional distillation

• Melting point

• Boiling point

• Density

• Viscosity

A fractional distillation column is hottest at...

• The top

• The middle

• The bottom

• The side