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Very interesting question - and thorough. But I would like to get proof that the spot is due to moisture. #1 Does the spot grow and shrink dependent on the relative humidity at that position? #2 If the spot is misted with a water sprayer, is it sharply defined? #3 If the spot is gently warmed with a space heater, does it disappear? #4 What color is the ...


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Despite your question is a bit vague about the sample, I assume «when they are in motion» refers to particles passing a tube, are close to each other -- in contrast to particles floating in air. If so, than you should consider to couple infrared spectroscopy (about the energy band) with a probe based on attenuated total reflection. Roughly speaking, ...


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It depends on the current humidity. Water vapor certainly does evaporate from ice, as you can see in a vapor pressure chart. If the humidity is 100%, and the air temperature is the same as that of the ice, then the evaporation and condensation are in equilibrium; i.e. water evaporates as fast as it condenses, so there is no net change in humidity. However,...


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As Ivan Neretin pointed out in his comment, there is no simple formula on this matter. Howevr, if you have access to ammonium nitrate ($\ce{NH4NO3}$) or sodium nitrite ($\ce{NaNO2}$), saturated solution of both give 64% relative humidity (RH) at $\pu{25 ^\circ C}$ (Engineering Toolbox). Interestingly, magnesium nitrate ($\ce{Mg(NO3)2}$) gives exactly 60% RH ...


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"Completely dry"? No, because molecules are always moving and there will be some exchange between desiccant and air. If you mean "below 10% relative humidity (RH)", there are a number of ways to do so: Consider that another way to discuss humidity is the dew point. Use a cold trap: after drying the air with a desiccant, pass the air slowly through a U-tube (...


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Your suggested use is impractical to dehumidify a living space, though it might help keep humidity down to ~75% in an enclosure. The issue is that air holds a fair amount of water. At 30°C, 100% humidity (i.e., dewpoint of 30°C), not untypical for a "mild" Georgia (US, not Republic thereof) day, that's 30 g/m3. If you were to buy a 22 kg block of ...


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Does it stay like thay when you remove the pressure and take it to the normal air? if yes, then it is likely co2 is being absorbed into the plastic part, and that plastic part is swelling. You can avoid it by using a glass window for optical sensor. Or use H2O permeable but not CO2 permeable membrane if this sensor needs contact with the gas. Or use another ...


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To have 100% relative humidity at constant temperature, 3 conditions have to be met: There must be water source to saturate space with vapour. There must not be present materials absorbing humidity below 100%. There must be allowed enough time to reach saturation. E.g., if there is solid table salt exposed to air, the equilibrium relative humidity would ...


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This problem is sloppily worded and, technically, it is not possible to give a definitive answer based on the information provided. But the missing information is not what you think -- you don't need to know the air pressure in the flask. What's missing are two key pieces: The degree of humidity ("humid" doesn't mean "saturated") and the volume of water ...


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