CHAP. 1: BASIC TERMS [CONTENTS] 26
Solution
If we are, from the thermodynamic point of view, interested solely in the liquid content of the
bottle, the system is homogeneous. It contains one liquid phase (a mixture of water, ethanol and
some additives). If, on the other hand, we are interested in the entire content of the bottle but
not the bottle itself, the system is heterogeneous. In this case it consists of two phases, liquid and
gaseous, with the latter containing air and whisky vapour. If, however, we focus our attention
on both the bottle content and the bottle itself, we have a heterogeneous system again, but this
time it also contains other phases in addition to the gaseous and liquid ones, i.e. the glass of the
bottle, its cap, label, etc.
