What causes the condensation at the top part of a 2 liter that has been opened and put in the fridge for awhil?
I noticed that also it expands and when you open it, it releases air.
- PaulCypLv 79 years agoFavorite Answer
Some of the remaining liquid, which is primarily water, evaporates, creating water vapor in the air space above the liquid. Chilling the bottle causes water vapor that makes contact with the bottle to condense on its surface. In addition to water vapor and air, there is a high level of carbon dioxide in the space above the liquid. This is the gas that gives the soda its "fizz". It is this gas, escaping from the liquid, that causes pressure to build, pressure that is released when the cap is loosened.