Upon opening a bottle of beer, you notice a cloudy haze that forms in the neck o

Question

Upon opening a bottle of beer, you notice a cloudy haze that forms in the neck of the bottle above the level of the beer. This cloud was not there before the cap was removed. Please explain quantitatively. Hint: Beer is mostly water; most mass-market beers seem to be entirely water. The pressure inside the neck of a bottle of beer is approximately 2 atm (about 2000 mb). Refrigerator temperatures vary, but most are around 40F. Compute how high the RH could get in the neck of a beer bottle immediately after the cap is removed.

Explanation / Answer

1) "Beer is Mostly Water", at the temperature of around 40 degrees F & pressure of approximately 2 atm. When the beer cap is removed, a fog is formed on the neck of the bottle right above the surface of beer in bottle, that's because of the sudden meeting of cold beer to the atmospheric pressure and temperature outside the bottle, just like the formation of fog over the surface of river or lake water in winter season, this happens when hot air meets cold air/water vapors (Humidity). when water vapors goes down below the dew point, it starts to combine (it might be seen in clouds as rain drops). Like formation of ice crystals is opposite of this.
2) RH (Relative Humidity) = Pw/Pws x 100%
Here the pressure & temperature of beer is given. So, as per gas law, for a given mass & constant volume of an ideal gas, the pressure exerted on the side of its container is directly proportional to its absolute temperature.


1)"Beer is mostly water", the cloudy haze form on the surface of beer in the bottle because when cap is removed, the water vapors of cold beer meets the air of atmosphere outside of beer bottle, this process is like formation of fog over the surface of a river or a lake in a cold morning, when the humidity of cold beer meets the air of outer atmosphere of bottle which is warm, then the water molecules of beer bottle condensed & a fog is formed on the surface of beer in bottle. This is called the dew point.

2) The Relative Humidity (RH) = Pw/Pws * 100

the pressure and temperature of beer is giver, so according to gas law, for a given mass and constant volume of an ideal gas, the pressure exerted on the sides of its container is directly proportional to its absolute temperature.

Related Questions

Navigate

• Browse (All)
• Browse U
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.