[Arkcon]

Since the main question has been answered I thought I'd ask one of my own: why do we need the thermometer to measure temperature here? Aren't we just performing a synthesis?

That is a funny one, for sure.  I guess once the reaction is complete, distillation is done in situ, which certainly makes more sense than transferring with a loss.  Still, is it a reaction and distillation, or a reaction that produces excess heat that distills off product, or a reaction that needs hear to start it, then need less heat as it progresses to prevent loss (the water bath would help in this case.)

[Big-Daddy]

Since the main question has been answered I thought I'd ask one of my own: why do we need the thermometer to measure temperature here? Aren't we just performing a synthesis?

That is a funny one, for sure.  I guess once the reaction is complete, distillation is done in situ, which certainly makes more sense than transferring with a loss.  Still, is it a reaction and distillation, or a reaction that produces excess heat that distills off product, or a reaction that needs hear to start it, then need less heat as it progresses to prevent loss (the water bath would help in this case.)

The heat is clearly being delivered by the Bunsen/heat source, the reaction does not have to produce it itself. But in any case I can't see why the temperature reached matters? You can see for yourself whether the condensation is occuring or not.

[sjb]

Since the main question has been answered I thought I'd ask one of my own: why do we need the thermometer to measure temperature here? Aren't we just performing a synthesis?

Part of the characterisation of a new compound, may be for instance a boiling point (or confirmation of a reaction giving a known compound). Perhaps less so these days, what with fancy NMR / LC-MS / CHN equipment, but it's still useful information to have...