Final answer:
In a mixed gas cylinder at 200 bar, CO₂ could be in a supercritical or liquid state above its critical pressure, but due to the presence of nitrogen and room temperatures, it is likely to remain gaseous. The gas mixture ratio should remain stable under typical room temperature fluctuations.
Step-by-step explanation:
The question concerns the behavior of carbon dioxide (CO₂) in a mixed gas cylinder containing both CO₂ and nitrogen (N₂) at room temperature, specifically whether CO₂ would remain gaseous or become liquid due to temperature fluctuations. Carbon dioxide has a critical temperature of 31.1°C (87.98°F), which is well above room temperature, and a critical pressure of 73.8 bar (1071 PSI). Since the cylinder pressure is 200 bar, which is well above the critical pressure, and the temperature in the room is below the critical temperature, the CO₂ within the mixed gas cylinder could potentially be in a supercritical or liquid state depending upon the actual amount of CO₂ present and the volume of the cylinder.
However, due to the presence of 70% nitrogen, which is non-condensable at these conditions and the relatively high temperature of 20°C to 22°C, it is likely that the CO₂ will remain in a gaseous state, mixed with the nitrogen.
It's also important to note that the gases are in a statistical mixture, meaning that the individual gas molecules are randomly distributed throughout the cylinder. Therefore, assuming the gases are ideal, the mixture ratio should not be significantly disturbed by minor temperature fluctuations within the designated room temperature range.