i would theorize that the opened one would chill faster only if it had been opened while hot. Carbonation escapes quicker at higher temperatures. This also brings up the oddity that hot water freezes faster than cold water - this being because molecules still need to move around to crystalize and since hotter molecules move faster, they can crystalize faster. OK. so it's not an answer, but it is an interesting thought anyway.

It is my understanding that the myth about hot water freezing faster than cold water is just that: a myth.

The initial idea behind freezing hot water wasn't because it froze more quickly, but because freezing boiled water [specifically] resulted in clearer ice cubes, which is not a myth...but who has the time to boil water to make ice cubes? If you've ever watched the show "Unwrapped" they did a brilliant segment on [of all things] Ice Cubes.

But this doesn't contribute to Matt's query.

Stu is correct, more carbonation is lost when opening a room temperature bottle of carbonated beverage than a cold one.

A bottle of water will chill fast and colder than a bottle of soda, so I will say that the opened-then-closed soda bottle [with less carbonation] will chill faster than the unopened bottle.

The higher the pressure on a gas, the higher it's temperature. When you open a soda, you're releasing the pressure, therefore as a result, I'd guess the opened one would cool faster.

For science fair me and my partner is doing which pop will freeze faster we are doing mountian dew, serria mist, diet pipsi, coke, cherry coke. Can you helps us on how to do this porject we want to do this porject because i was all way woudering what pop will freeze faster.HELP US PLEASE