What keeps the carbonation in your soda from escaping all at once?

Question

What keeps the carbonation in the soda from escaping as soon as you open the lid/cap? Why doesn't it just all turn into gas all at once? I'm guessing it's kind of like boiling water, the carbonation turning from liquid to gas, but it doesn't appear to require heat to fuel the process. If it did, I would think the soda would be cool to the touch due to the process (since it would be carrying the heat away in the CO2 gas).

Answer 1

Temperature and pressure determine how much gas can be dissolved into a liquid. Cooler temperatures and higher pressures result in more gas being dissolved in the liquid in question.

As temperatures rise and pressure lowers, the amount of carbon dioxide released increases till an equilibrium is reached where the gas does not attempt to escape (or escapes slowly) until acted upon (shaking, adding nucleation points, increasing temperatures or pressures even more, etc)

And as a side note, you can watch violent nucleation occur by adding about a quarter cup of sugar to a bottle of soda really quickly....

Just be really careful... it's reasonably safe to do but the reaction can be quite surprising, messy, violent, and the bottle may 'fly' all over the place and hurt something. You assume all the responsibility for doing this.

:-P

Answer 2

Gasses are actually soluble in liquids. The carbon dioxide is dissolved in the soda, and is no more inclined to spontaneously separate out than is sugar dissolved in coffee. But gases are more soluble in cold liquids (unlike solids, which are more soluble in hot liquids), which is why soda fizzes up more if you open it for the first time without having refrigerated it; the gas is injected into the soda at a cold temperature, and it has become supersaturated at almost any domestic temperature. The gas escapes until remaining only at the saturation level. Over time, gas continues to leave the soda because it is more soluble in the surrounding air and the soda bottle is not completely airtight.

Answer 3

The process requires energy. Get it? Heating it would speed up the process. Under normal conditions, the rate of heat absorption is not that high due to a small difference in temperature. That is why it only happens slowly and the whole can does not turn cool as this violates the Second Law of Thermodynamics (heat would not travel spontaneously from a cooler region to a warmer region.)

Answer 4

CO2 cannot easly escape as single molecules (except at the surface) it has to be able to form a bubble. This requires a large number of CO2 molecules to come together this does not happen too often except at nucleation points where bubbles can be initiated and remain stable. Diffusing molecules allow the bubble to grow until it is self bouyant.

Answer 5

ok CO2 is always a gas it's just in solution. if you heat it it will all come out of solution. also the design of the bottle/can helps keep the beverage carbonated longer. narrow opening limits the reaction of CO2 coming out of solution.

Answer 6

surface tension.