Questions tagged [sublimation]
The process of a substance transitioning from solid to gaseous phases, and vice versa.
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What were the crystals I saw in a package of caffeinated mints?
I opened a package of caffeinated mints this morning, and I noticed that they seemed to sparkle in the light. When I examined it closely, I saw that the "empty space" in the package was full ...
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In a perfect vacuum, shouldn't every solid be above its sublimation point, since its vapor pressure must exceed the atmospheric pressure?
If the sublimation point of a substance is the point where its equilibrium vapor pressure exceeds the pressure of the atmosphere upon it, and if every solid above absolute zero has some vapor pressure ...
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In a vacuum, what gas(es) emanate from ilmenite when heated degree by degree to very high temperatures (complete sublimation)?
In a vacuum, ilmenite $\ce{FeTiO3},$ like all matter, sublimates to gas(es) if heated to a high enough temperature. If our (already purified) ilmenite sample (at $\pu{0 Pa}$ pressure and no reactants ...
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Question regarding enthalpy of sublimation vaporization and fusion
While learning Thermochemistry, I came across the formula
$\Delta H_{sub} = \Delta H_{vap} + \Delta H_{fus}$
Now my question is how that when we want to change the phase of a substance from solid to ...
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Separation of benzoic acid and naphthalene from its mixture [closed]
The best method for the separation of naphthalene and benzoic acid from their mixture ?
a)chromatography b)crystallization
c)distillation. d)sublimation
many sources says answer is crystallization ...
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Sublimation as a separation technique
During a lecture, my professor said that sublimation at atmospheric pressure (1 atm), as a purification/separation technique, can be performed when the sublimating substance has a triple point falling ...
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Are volatile impurities an issue for sublimation as a purification method?
Recrystallization depends on identical solute molecules colliding so that a crystal can grow. An impurity present in low concentration will generally remain in solution because kinetics will favor ...
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How is it possible that some celestial bodies have icy surfaces when water boils off at any temperature in absolute vacuum?
Why doesn't the ice on comets or on the moon Enceladus sublime? Enceladus doesn't have an atmosphere, so what is it that prevents Enceladus' water ice surface from becoming a gas? Did I miss something?...
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How does water sublimate at normal atmospheric pressures/conditions (i.e., without a phase boundary between solid and gas)?
I remember my high school chemistry teacher stating that water could sublime under normal atmospheric conditions that would exist in e.g., Lancaster County, PA, where Amish would hang clothes to dry ...
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Is it appropriate to say "solid-in-gas solution" and "liquid-in-gas solution"?
A number of books mention "solid-in-gas" and "liquid-in-gas" types of gaseous solutions.
However, for something to dissolve in a gas, it must be in its vapour phase. So, for ...
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Why are camphor vapours taken in nitrogen gas?
I have read some examples of "solid-in-gas" solutions in several books. These examples include iodine vapours, camphor vapours etc.
However, one fact that has stuck me is that nearly every ...
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What is the difference between sublimation and instantaneous fusion+vaporisation?
Sublimation is defined by the IUPAC as The direct transition of a solid to a vapour without passing through a liquid phase.
A sublimation equilibrium can occur in two sets of conditions:
at a ...
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Ice sublimes on the moon? [closed]
I read that the ice sublimes on the moon as the vapour pressure will be really low, but won’t a low vapour pressure increase the boiling point?
(Might be wrong, kindly don’t judge.)
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Internal energy for Phase Transitions
Can we justify that "For sublimation of a solid at 1 atm $\Delta U>0$ at low temperature and $\Delta U<0$ at high temperature?"
I read several answers and came to know that $U=f(T)$ ...
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What is the triple point pressure for Gallium?
I have seen various discussions about the triple point of Gallium determined to a very precise value, so precise that it is used as a reference for NIST scales and measurements.
However, these ...
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Why does snow sublime even when the surrounding temperature is below 0 °C? [closed]
Snow in winter below 0 °C, still sublimed very slowly over time. If I’m not mistaken, sublimation is an endothermic process. Where is this absorbed energy coming from when the surrounding temperature ...
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Why does substance that sublime not come to liquid state? [duplicate]
A substance that sublimates doesn't come to a liquid state at room temperature. But when we melt the substance it melts! Why does it skip the liquid state at room temperature?
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Calculate Gibbs energy of dinitrogen pentoxide using its vapor pressure and sublimation
I am having trouble with the following problem:
Dinitrogen pentoxide, $\ce{N2O5}$, is a solid with a high vapor pressure. Its vapor pressure at $\pu{7.5 °C}$ is $\pu{100 mmHg}$, and the solid ...
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Why is sublimation considered a zero-order process?
In my Chemistry book, it states that sublimation is normally a zero-order reaction or process, as the concentration of molecules that have sufficient energy to sublime is limited by the solid's ...
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Can a solid have a vapor pressure without the ability to sublimate?
Does sublimation occur when a solid turns into a gas and THEN vapor pressure is produced or does the solid first have a vapor pressue and then when the vapor pressure of the solid equals the ...
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Lyophilization Advantage
I've been reading about freeze drying and how it increases the shelf life of certain foods and is overall a good preserving technique.
My question is with regard to the actual process. I understand ...
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Calculate Heat of Atomisation [closed]
What is heat of atomisation of P4O6(s) Given heat of sublimation of P4O6 is x kJ/mol & P–O bond energy is y kJ/mol.
What is heat of atomisation of P4O6(s) Given heat of sublimation of P4O6 is x ...
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Why does the gas from dry ice flow down?
I am reading Dan Broughton's answer in replying to the question "why does the gas from dry ice flow down" here.
According to the answer, the fog is water's color and water is condensed and suspended ...
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Is there a method to recover camphene from sublimation at ambient conditions?
Camphene solidifies and sublimates at ambient room temperature below 45°C. I'm aware that a glass funnel is often used to separate mixtures through sublimation of the volatile component (in this case ...
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Why does CO2 only exist in gaseous and solid state under STP/SATP?
Why does carbon dioxide only exist in gas and solid state under STP/SATP conditions?
$\ce{CO2}$ pressurized to $\pu{5.1 atm}$ can exist in all 3 states: solid, gas, and liquid.
However, why couldn't ...
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What are the side effects of adding dry ice to a swimming pool?
My apartment complex pool was closed today due to a resident dumping a large quantity of dry ice into the pool. In the notification from my landlord, they stated:
Dry ice is frozen carbon dioxide ...
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Why does the crystal sublime more quickly at the corners where there is a higher vapour gradient?
The crystal responds to the larger vapor gradients near the edges by
sublimating faster there and thus rounding the crystal.
J. Nelson, J. Atmos. Sci., 1998, 55, 910-119.
The change in shape ...
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Nucleophilic Substitution Reactions help
Which halogenoalkane reacts fastest with sodium hydroxide?
A. 1-iodobutane
B. 1-chlorobutane
C. 2-chloro-2-methylpropane
D. 2-iodo-2-methylpropane
Iodine has a larger radius, thus less ...
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Does naphthalene in moth balls really sublimate or does it evaporate?
The triple point of naphthalene is $\pu{-56 °C}, \pu{1.05 kPa}$ (which is much less than $\pu{1 atm}$). So how can a naphthalene ball sublimate at $\pu{1 atm}$, when considering that its melting point ...
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Is it correct to say that SOME iodine undergoes sublimation at 1 ATM
The triple point of Iodine occurs at 0.12 atm and at standard temperature it is a solid on the phase diagram.
I understand that therefore, when heating iodine at 1 atm, it (at least some of it) will ...
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What are disadvantages of using sublimation vs. recrystallization as a method of purification?
I can only think that a small sample can be sublimed while a bigger sample size can be recrystallized. Are there more?
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I suspended iodine over steel nails. What are these droplets that formed?
I suspended about 15g of iodine crystals over a couple of nails to see how quickly they would begin to rust.
After a week, these droplets had formed. When prodded they broke apart like water drops.
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Sublimation and recrystallization of caffeine
I'm looking to do an extraction of caffeine from energy drinks. I want to use both sublimation and recrystallization in my experiment for advanced purity.
My question is which should happen first, ...
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Vacuum at different altitude
I have tried to find this searching the internet and I am not sure if I understand it. I want to turn water from solid to gas without going into the liquid phase - Sublimation.
The altitude above sea ...
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Sublimation of Iodine from Iodine Povidone
Iodine povidone is a complex of iodine and the polymer povidone. I am wondering if one were to heat it enough, the iodine would sublimate and could be collected. Normally iodine boils at 184.3 °C, ...
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What is the lowest temperature tungsten starts sublimating at?
What is the lowest temperature tungsten starts sublimating at? I've tried to search in Google but without any luck.
For example, $\ce{WO3}$ starts sublimating roughly at $\pu{550 °C}$, according to ...
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Equilibrium saturation/depostion rate calculation
I found the Knudsen/Langmuir equation for calculating the sublimation rate of a solid. If I have a closed system, once the vapor reaches the saturation pressure, the solid will continue sublimating ...
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What is this glassware?
I found this in a second hand store, and I think it has to do with freeze drying. Is there any validity to this assumption? What is this called? Also, the little tuberculina at the bottom are stuffed ...
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How to create liquid carbon, and what kinds of properties does it have? [duplicate]
Carbon sublimes at about 3915K. In a high pressure environment, shouldn't it be possible to create liquid carbon at high temperatures? Has this ever been done? What does it look like and what ...
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Why does dry ice "dissolve" so quickly in water?
I just stumbled across an ancient video of some people putting a 60 pound block of dry ice in a swimming pool. Pretty cool stuff.
It's pretty interesting to me that in the video, the dry ice ...
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Sublimation of Iodine
Why does iodine sublime? I have researched it myself and I have got the same answer; it sublimes because it directly converts from solid to gas. But why don't bromine or chlorine also sublime?
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If you can smell something does that mean that this thing loses molecules?
When you can smell something there must be some molecules in your nose which signalize the smell in your nose. Does that mean, that e.g. a cheese is losing molecules which fly into your nose?
And does ...
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Drying Clothes Outside Below Freezing
It is commonly accepted that you can hang your wet clothes outside to dry even when the winter temperature is below freezing. It is mentioned here
http://grist.org/living/ask-umbra-can-i-line-dry-my-...
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How fast will hydrazine boil out of a tube into a vacuum?
For context I'm talking about ISEE-3 and how long it would take to dump the now useless and hazardous fuel it still carries.
Given a heated tank of hydrazine (somewhere near $0~^\circ\mathrm{C}$) ...
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Is sublimation a property of all substances?
I wonder if sublimation can be done only on certain substances like iodine, or it can be done on all substances.
In other words, can sublimation be done, for example, on water? If it cannot, then why?...
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Is sublimation caused by an environmental difference or an element's composition?
I was having a conversation when the topic of sublimation came up. Prior to the discussion, I had always thought that sublimation was caused by a great pressure/temperature difference, but another ...
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Which elements have no liquid form at atmospheric pressure?
Carbon has no liquid form at atmospheric pressure. Is this unique amongst naturally occurring elements?
The more interesting and vague question is, is this property somehow important or related to ...
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What is known about liquid carbon?
The wiki tells me that if you heat carbon at atmospheric pressure it eventually turns directly into a gas without being liquid first. At what pressure can you make liquid carbon? Has anyone actually ...
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