It’s important that students are able to understand the chemical ideas behind these practical procedures: it’s easy to simply let them do the experiment without giving them the additional challenge of gaining the understanding.

Match the statements to the process that offers the best opportunity for learning.
Statement Fractional distillation Cracking
In fractional distillation we rarely obtain the amounts of fractions we want.
There is a gradual change in physical properties from one fraction to the next.
In fractional distillation separation occurs over a boiling range rather than sharp boiling points.
Larger molecules can be converted into smaller molecules by heating and/or catalysts.
The catalyst in the experiment has to be porous because the cracking occurs on the large internal surface area.
Higher RMM hydrocarbons have a higher boiling point.
Different hydrocarbons can be separated because they have different boiling points.
There are two products – an alkane and an alkene.
The catalyst has to be hot in order to work.
Crude oil is a mixture of hydrocarbons.