|MadSci Network: Chemistry|
WITH all other things being the same:
Ethanol (pure) has a specific heat of 0.55 cal/gram*celcius degree.
In light of these differences - I would have to say that the solution with the most water (80 proof) would have a higher capacity to melt ice, thus probably giving it a slight advantage over the 100 proof. In order to melt ice you must supply it with heat, water can supply about twice as much heat to the ice before it is cooled to the temperature of the ice. Ethanol cannot supply as much heat.
I have not taken into consideration the freezing point of ethanol (–114.1° C) But since the ethanol and water are mixed their numbers become less fixed and as the ice melts they change even more.
BUT your question was concerning the speed of melting.
The differences between the two solutions is only 5%.
So it is not suprising that you didn't notice a difference nor can I think of a practical way to test this, with accuracy.
I would have to say there is a slight advantage to the solution with more water ( 80 proof) but only a slight advantage.
Hope that helped.
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