This demonstration should reinforce the message that during smoking, even with filter cigarettes, the human body inhales tars that are now known to be carcinogenic.

The energy changes involved in chemical reactions are often illustrated with this reaction.

The chemistry of extracting substances from plant materials is important because many such compounds are physically active, either medically or aesthetically (perfumes).

This practical illustrates the idea that oxygen has mass, and that burning can involve an increase in mass as an element reacts to become an oxide. The activity also introduces the idea that the relative mass of elements in a compound is in the same proportion as the atoms in the chemical formula.