Sublimation Definition and 32 Threads

My son is in year 7. I received a test paper and his answers. Unfortunately, we don't have the correct answer for some questions. I have attached the screenshot. The topic is particle model (year 7). I would appreciate your help. This is not a homework question but I need your expert advice so...

How long does it take water ice H20 in space in our solar system to sublimate, say a basic ice cube? It starts as a solid cube at the temperature of whatever space is above Earth and then completely turns to vapor. Just looking for ballpark situation here. Does anyone know of a table or place...

Having watched a dropped cube of ice sublime to nothing at the bottom of the freezer of my refrigerator in my kitchen over the course of a week, I would like to know why comets don't do this. Presumably the tail is the product of sublimation, but how long can that go on? How can Halley's Comet...

Hello, I have a little difficulty understanding how sublimation works, from what I have understood so far, the sublimation of ice for example occurs below its triple point (at a certain pressure and temperature but not atmospheric pressure but at a certain partial pressure). Does this mean that...

Question for materials scientists: All solids evaporate (or sublimate) over some time, even steel. Could the sublimation of steel over time be prevented or slowed with a coating? EDIT: Do diamonds themselves sublimate in a vacuum?

Hello, I am running experiments where materials are heated at high temperatures during tens of hours under high-vacuum conditions. Since what I am investigating lies in the first hundreds of nanometers of the materials, I must take into account (and anticipate) surface sublimation. Therefore I...

Before this question, the questions were about the Clapeyron equation, and how to estimate ##\Delta s##. I'm completely put off by this question however, and don't know where to start. I've found that the triple point of water is at ##0.01°C##, and there is indeed data in the table for...

Homework Statement Using the heats of fusion and vaporization for water, calculate the change in enthalpy for the sublimation of water: H2O(s) --> H2O(g Using the delta H value given in Exercise 24 and the number of hydrogen bonds formed to each water molecule, estimate what portion of the...

In my Thermodynamics course, we recently learned about the saturation pressure and saturation temperature of different substances -mainly water. As you know, the saturation temperature at which a substance begins to boil is specific to a fixed saturation pressure. Water only boils at 100...

Homework Statement Below, two experiments (1 and 2) are described, in which the same quantity of solid carbon dioxide is completely sublimated, at 25ºC: The process is carried out in a hermetically sealed container, non-deformable with rigid walls; The process is carried out in a cilinder...

Liquid water sitting can evaporate without a problem, given that the vapor pressure surrounding it is less than the temperature dependent saturated vapor pressure. Similarly, an ice cube can also evaporate without becoming liquid under these same conditions. However, an extreme form of...

I want to reduce the amount of water present in the digestate coming out of my Anaerobic Digester. The traditional method would be to boil it until I've removed as much off as I want. However, this is expensive from an energy consumption point of view. There's a great video on Youtube showing a...

Homework Statement Multiple choice:[/B] In which of the following processes are covalent bonds broken? a) solid sodium chlroide melts b) bronze melts c) sucrose dissolves in water d) solid carbon graphite sublimes e) solid carbon dioxide sublimes Homework Equations none The Attempt at a...

A coworker posed a thought experiment; if you sealed a sample of frozen CO2 in an uncompressable container of identical volume and allowed it to warm to room temperature, how could it melt/evaporate, since there would be no room for the gas to expand My guess is that it would sublimate to a...

I know that Arsenic sublimes directly when heated. So I want to know which other elements like this sublimates on heating throughout the periodic table. I also know dry ice. thanks

Homework Statement The problem is this: what is the optimum amount of dry ice inside the Styrofoam pack, if we want to received a frozen dough (temp.-18) after 3 days of transportation in temperature 20 C ? My calculations and data placed in the attached excel file, but I'm not sure if they...

I am trying to find references for the the Wikipedia article Frost line (astrophysics) I am having a hard time finding a reference for the "Sublimation temperature of water in vacuum" that is used for calculation of the current snow line. E.g.: I have found 150K in several places, without any...

Hi all, I am forced to step outside of my field to investigate a problem that might root in sublimation of solids. I am trying to calculate the mass (after a certain time) of a material that we know is sublimating at , say .000123 g/(cm^2 hr). Is it as simple as multiplying the rate by the...

Well! the material to be freeze-dried is irradiated with IR radiations before, why?? Also I am confused as to how can ice sublime at atmospheric pressure?? Isn't the triple point of water much lower? is the vacuum around the material created for this reason? ( to lower the pressure I mean) Also...

Homework Statement The standard enthalpy of sublimation of dry ice (solid carbon dioxide) is 6.03 kJ/mol. The triple point of CO2 is at 5.1 atm, -59.7 °C. Calculate the normal sublimation temperature of CO2 at 1.00 atm pressure. Homework Equations Delta G= Delta H-T(delta S)...

Homework Statement When fluorine and solid iodine are heated at 550. K, the iodine completely sublimes and gaseous iodine heptafluoride forms. If 350. torr of fluorine gas and 2.50 g of solid iodine are put into a 2.50 L container at 250. K and the container is heated to 550. K, what is the...

I have a pretty stupid question that I hope someone can answer. I'm trying to deposit chromium and vanadium in UHV, and I need to determine whether each of the materials will "melt" or "sublimate" so that I know the volume to fill my crucible. My impression is that these materials will...

I am wondering if I can separate these two compounds: Y: M.P.=170 degrees C - Vapor pressure at its MP = 0.05 torr Z: M.P.=170 degrees C - Vapor pressure at its MP = 540 torr I think having a huge difference in vapor pressures is good. I am kind of confused about this process.

Hi, I did a pressure rise test on a chamber, where I closed the isolation valve and measured the increase in pressure over 30 seconds. I want to use this information to calcualte the rate of accumulation of vapour in the chamber. What I'm looking for is the sublimation rate during freeze...

Homework Statement How can ice sublimate at atmospheric pressure? Looking at the p-T diagram for water, the sublimation curve does not extend above a tiny fraction of atmospheric (triple point of water, p = 4.58mm Hg). Yet my ice box tells a different story. Homework Equations...

Hello, Please forgive my ignorance, although bright, I was a lousy student, & never took physics in school. I find it frustrating when relatives & friends are uncertain as to how to respond to questions like those below, so your educated reply would therefore be all the more appreciated...

Hi, Does anyone know what ablimation is? Is it the same as sublimation? Regards

Why caffeine has 178 oC as point of sublimation but 237 oC as melting point? Is it about the pressure? If so, then what is the preesure that makes 237 as melting point instead of sublimation at 178 oC? Cuz the science websites always just said 237 is the melting point, but didn't mention the...

Homework Statement How much ice (in grams) would have to melt to lower the temperature of 351 ml of water from 24 deg C to 5 deg C? (Assume the density of water is 1.0g/ml .) Homework Equations q=mc(deltaT) The Attempt at a Solution m=351 g c=4.18J/g*C deltaT=19deg C...

On what principle does a substance sublime? I mean , does it work towards thermal equillibrium and hence the gain in heat raises the Kinetic energy to hence change the state to vapour? But then sublime substances still sublime when equillibrium has been attained.

Why is is that certain substances, (example: solid carbon dioxide) can undergo sublimation and turn into gas without undergoing liquid form when heated? What is the general characteristics that enable certain substances to undergo sublimation? Is it possible to have a substance that can...

Any one knows the reason for the Sublimation( solid to gas). I think the attraction between the air molecules and the weaker molecular stuctured solid molecules. its and adhesion effect. the molecules in surface of the solid is being attracted by the air molecules ( such like polar molecules NO2...