User`s guide

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c. Common internal pressure range of soda cans
Gases exert a pressure on any surface with which they are in contact. The amount of pressure exerted by
the molecules of a gas depends on the force and frequency of the molecules towards the walls of its
container. The pressure of gases is therefore dependent upon temperature and volume. The Third Gas
Law states that when the volume of a fixed mass of gas is maintained constant, pressure is directly
proportional to absolute temperature.
Soda manufacturers often inject cold liquid with pressurized carbon dioxide, then bottle the drink under
high pressure. This is due to the fact that more gas will dissolve in a cold liquid that's under a high
pressure than in a warm liquid that is not under pressure. The carbon dioxide in the soda forms carbonic
acid, which alleviates the sweet taste of the drink. The carbon dioxide also serves an anti-microbiological
purpose.
Each type of soda drink contains a different amount of carbon dioxide, and thus has varying amounts of
pressure. On average, the 12 ounce soda cans sold in the US tend to have a pressure of roughly 120 kPa
(17psi) when canned at 4 °C, and 250 kPa (36 psi)when stored at 20 °C.
Specifically, a refrigerated can of 7UP® contains 210 kPa (31 psi) of pressure. On the other hand, Pepsi-
Cola® contains 276 kPa (40 psi) at approximately 16 °C. Lastly, a can of Coca-Cola Classic® at 34 °C
has an internal pressure of approximately 380 kPa (55 psi).
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Pressure in a can of soda. (n.d.). Retrieved Dec 2012, from The physics fact book:
http://hypertextbook.com/facts/2000/SeemaMeraj.shtml