CHEM一問 有關冰或乾冰

The white solid is ice.
該白色固體是冰。

In the fire extinguisher, carbon dioxide is compressed to be liquid. The pressure is greater than 5.11 atm,because carbon dioxide exists as liquid only when the pressure is greater than5.11 atm. When pressure is released, andcarbon dioxide liquid in the extinguisher is rapidly evaporated to be vapour whichshoots out through the nozzle. Theevaporation of carbon dioxide is endothermic, and the heat content of air(including water vapour) is absorbed. Thetemperature of the air near the nozzle drops sharply and falls below thefreezing point (melting point) of water. Thus, water vapour near the nozzle is changedrapidly to water drops and then ice rapidly. Other components of air have much lower boiling points and freezingpoints than water, and thus are still gaseous. After some time, the ice formed absorbed heat from the surroundings andis then changed to liquid water.
在滅火筒中，二氧化碳被壓縮成液體。壓強在 5.11 atm 以上，因為在 5.11 atm 以上二氧化碳才會以液態存在。當釋放壓力時，滅火筒內二氧化碳液體快速氣化成蒸氣，由噴咀噴出。二氧化碳的氣化是吸熱的，吸收空氣（包括水蒸氣）的熱含量。噴咀附近空氣的溫度急速下降至低於水的凝固體（熔點），因此噴咀附近的水蒸氣急速變成水點然後變成冰。空氣的其他成份的沸點和凝固點都遠低於水，故此仍呈氣態。一段時間後，冰吸收周圍環境的熱，變回液態水。

On the other hand, the solid is NOT dry ice (carbon dioxide solid). This is because carbon dioxide is solidifiedat a much lower temperature (-78°C). Beside, dry ice would be sublimed instead ofmelted into liquid in open atmosphere.
另一方面，該固體不是乾冰（二氧化碳固體）。因為二氧化碳在較低溫度（-78°C）才會固化。此外，乾冰在大氣中只會昇華，不會液化。

個d應該係水尼
乾冰唔會變liquid啦當然:)

唔知你有無打邊爐尼
butane會被store as liquid in the bottle
之後你就用做fuel
佢因為加壓先變liquid
當你開佢 佢變做gas時會吸收energy
(liquid係低能的 gas係高能 低能變高能要加能)
咁支野就會好凍
water vapour/droplet遇到ed cold surface就會變liquid

我覺得係開個滅火筒時
個咀個度好凍 water 甚至ice form左係個度

ps. 個野噴既係CO2 可能佢一開始store in high presure/ any else