The components in a heterogeneous mixture must exist in a single phase (solid, liquid or gas).

hetero = different and geneous = nature. If you take random samples from different parts of a heterogeneous mixture, you get a different mix of components. Think sand and water, then let the sand settle out and then take samples.

Ithink this is what you meant. the temperature at which a liquid begins to boil is called the boiling point. the boiling point of water is 212°f or 100°c.  and at that point will start to turn into steam (gas)