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Questions tagged [phase]

An entity of a material system which is uniform in chemical composition and physical state. This tag should be applied to question regarding chemical and physical properties of phases, systems of phases and also phase transition processes.

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Composites of Immiscible Solids - Aluminum and Lead Example

The $\ce{Al}$-$\ce{Pb}$ (aluminium-lead) phase diagram clearly depicts that when cooled from the liquid state, aluminium and lead are not miscible in the solid state, i.e. the crystal structure of ...
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For homogeneous equilibrium, why are liquids and solids included in the equilibrium constant (when they aren't in heterogeneous equilibria)?

In a heterogeneous reaction (where the states are varied) we do not include liquids and solids in the equilibrium equation because their concentrations do not change. E.g. Chemguide.co.uk However, ...
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How long would it take for liquid oxygen to evaporate at room temperature?

I watched a video on youtube in making liquid oxygen. How long would it take for liquid oxygen or liquid of another gas (e.g. nitrogen or hydrogen) to evaporate and why would it not be instant? Could ...
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How is latent heat of vapourisation utilized in changing state?

If latent heat of vapourisation is utilized in overcoming intermolecular forces of attraction between the participle of a material then how is it still hidden there? If latent heat is used in ...
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Why is ice sticky between −20 to −8 degrees Celsius but not below −30 °C?

I was watching an Air crash investigation video where the cause of the plane crash was determined to be due to blockage of fuel pipes by ice crystals (from the water in the jet fuel) which would have ...
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Phase transition for an ideal fluid

Does a phase transition occur also for an ideal fluid (from ideal gas to ideal uncompressible liquid)? Or ideal fluids can be modelled only as ideal gas or uncompressible liquid at all, without the ...
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374 views

How can water exist in three states in freezing point?

Freezing point is temperature on which vapor pressures of solid and liquid are equal. This is definition from my book. How can water ice and vapor of those co-exist when water that is only possible in ...
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How does the London force work at absolute zero? [closed]

Consider a molecule such as pentane which is mostly attracted to other molecules by dispersion forces. If there is no heat and no fluctuations in electron positions how would a liquid or solid hold ...
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What would happen if I mixed a single water molecule in a beaker of hexane?

What would happen if I mixed a single water molecule in a beaker of hexane? Would it sink or float? How about 2 water molecules? 3? Etc? In other words, how many water molecules does it take to be ...
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370 views

Evaporation Rate of Water

In AP Chem we did a lab investigating the relationship between vapor pressure and water temperature. The relationship is linear and as the vapor pressure approaches atmospheric pressure, it begins to ...
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3 component (ternary) system in equilibrium

If the components of a system were Cl2, Br2, and I2, how could I describe this system under equilibrium conditions when the number of phases is at a maximum? If there are 3 components, using the ...
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112 views

For covalent compounds, what is the microscopic difference between a solid and a liquid? [closed]

I've got a question regarding the microscopic difference between liquids and solids. I know that there exists a precise phase transition between solids and liquids, so some discrete parameter must ...
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How do non-sublimable solids exist in equilibrium with vapour?

How do non-sublimable solids exist in equilibrium with vapour? All substances exist in equilibrium with their vapour, something I learned from Jan's comment. But my question is how does that happen ...
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Is glass an amorphous solid or supercooled liquid?

I have been informed that glass is a super-cooled liquid and is also considered to be an amorphous solid. Can it be both and, if not, what category does it fall into?
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Equation to calculate the triple point

Is there any equation that can calculate the triple point of a substance? Because a method for calculating the critical temperature and the Boyle temperature of a substance that I posted in another ...
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610 views

How much pressure does Gallium exert when it freezes?

Assuming the liquid Gallium is in a sealed container, how much pressure will it exert on its container when it freezes?
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Heating of mixture of gases with one gas barely above its boiling point

What happens when mixture of two gases is heated in a closed container? If one gas expands faster than the other and increases pressure of the container enough so that the boiling point of the other ...
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468 views

Heat Transfer during Phase Change

When ice is melting, we know that the temperature stays constant at 0 ℃. If we were to place ice at 0 ℃ in a sufficient amount of water at ambient temperature, would the temperature of the water ...
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214 views

Does any compound exist with multiple liquid phases?

I've seen some phase diagrams and I found really interesting, how many exotic solid phases of most elements exist on higher pressure and temperature. But I've seen always only a single liquid phase ...
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331 views

Mass of Ice during Phase Change

If 18g of ice at a temperature of -6 ℃ is placed in 250 g of water at 20 ℃, we know that there is enough energy supplied by the water to completely melt the ice and transform it into liquid. My ...
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Latent Heat and Kinetic Energy

The kinetic theory says that temperature is the measure of the average kinetic energy. That would mean then: The temperature rises with the rise in kinetic energy. We know that when matter changes ...
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494 views

Vapor-pressure or Vapor-concentration

To summarize from my textbook: rate of evaporation: proportional to surface area but essentially independent from pressure (of surrounding gas) rate of condensation proportional to both surface ...
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7k views

What is the pH of ice?

The pH of pure liquid water depends on temperature. It is about pH = 7.0 at room temperature, pH = 6.1 at 100 °C, and pH = 7.5 at 0 °C. What happens to the pH (or to the ion product) of pure water ...
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Why are naturally occuring liquids more rare than solids and gasses on Earth? [closed]

There are only a few naturally occurring liquids I can think of on earth, such as water, mercury and animal oils. Why are naturally occuring liquids more rare than solids and gasses on Earth? To be ...
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Calculating the mass of water removed by air conditioning condensation

I cannot figure out how to calculate the mass. The question is: "Suppose the percent relative humidity is $\mathrm{80.0\%}$ at $\mathrm{91.4\ ^\circ F}$ ($\mathrm{33.0\ ^\circ C}$) in a house ...
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Why so few fluid phases?

Taking a look at the phase diagram of water By Cmglee - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=14939155 I see ice phases as much as up to 'Ice XI', but only one '...
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Why is including phase info in chemical reactions important?

I would like to ask why do we have to include the phase change in a chemical reaction e.g from solid to aqueous or liquid. Why is it important actually?
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421 views

Is water committed to vapor state at boiling point or after? [duplicate]

Quite early into my studies, I learnt about phase changes with this graph. I’m just going to focus on vaporization/condensation. I learnt that the plateau was caused because all the heat was going ...
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259 views

Multiphasic liquid “flotation” experiment

I'm trying to create an experiment where two immiscible liquids are mixed and are then separated by density. Most of the container is occupied by the lighter liquid, and the small amount of heavier ...
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854 views

Volatile nature and odour

Will it be correct to make a general statement that all compounds having odour are volatile? My reasoning: if a compound has odour then to smell that it must evaporate ( ie. some molecules must ...
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51 views

Pressure increase on rate of reaction

For reactions involving gases, an increase in pressure is no different from increasing the concentration of reactant particles, thus increasing the rate of reaction. But for reactions involves ...
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Is tungsten gas visible?

I apologize if this isn't a sufficiently technical question to be posed in this forum. I'm planning a short story, and unfortunately I've worked in a somewhat sience-y opening. Most of the ...
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961 views

How does iceskating work?

I was willing to understand a little bit better the physics behind iceskating. Messy thoughts From New Scientist (1964) (probably not the most up-to-date reference $\ddot \smile$), I found a diagram ...
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What are the physical properties of exotic ice?

This chart shows the phases of water that form at various combinations of pressures and temperatures. It has multiple exotic forms of ice (labeled II through XV) listed. What are the physical ...
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Are there any gases more dense than liquids?

Inspired by Is there any type of liquid, other than mercury, that PTFE teflon is known to "float" to the surface in?, are there gases that are more dense than liquids? (So bubbles would sink ...
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Liquification of gas to liquid at critical temperature

The gas that liquifies first, when cooled from 500 K to its critical temperature given in parenthesis is a) $\ce{CO2}$ (304.1 K) b) $\ce{NH3}$ (405.5 K) c) $\ce{O2}$ (154.3 K) d) $\...
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How does ice melt?

I know that when water freezes, it forms a crystalline structure created by the hydrogen bonds between polar water molecules. Also, I know that during a phase change, the potential energy of the ...
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What is the structure of powdered sulfur?

Quoting this paper: A variety of allotropic states of elementary sulfur have been identified. Solid crystalline sulfur exists either as rings of 6-12 sulfur atoms (cyclohexasulfur, $\ce{S6}$, ...
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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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Does autoionization occur in steam?

It is well known that H2O spontaneously autoionizes to H+ and OH- when it is in liquid phase. I was wondering whether it does the same in gas phase, either to the same extent as in liquid phase or at ...
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Why do we consider all gasses to be in one phase?

Why do we take the phase of all gases 1. If all gases exist in 1 phase then why do we say that some gases are heavier than air, some are light also we collects some gases in lab by air displacement ...
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What happens to the bleach after mopping?

At home, I clean the tiled floors by mopping with highly diluted bleach. After mopping, I let the floor dry. What happens to the acid in the bleach? Will it crystallize on the floor, stay there ...
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overall energy and the boiling point

i need help with the fractional distillation method of a couple of substances at least more than two substances , just like air actually what am i looking for is that why do substances in air with a ...
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Are open system phase transitions physical equilibriums?

I have been told that phase transitions=physical equilibriums. How can phase transitions be physical equilibriums? For example, if you have liquid water going into gas phase, doesn't delta G have to ...
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At what temperature (in kelvin) are most of the elements on the periodic table liquids?

This question is out of pure curiosity. At what temperature are a majority of the elements on the periodic table in a liquid state/phase of matter? For the purpose of this question, assume the ...
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'Chemical' First-order Phase Change

First order phase changes occur when one local minima of the Gibbs Free Energy becomes deeper than another. Thus at 1 atm and 99 °C, the Gibbs Free Energy of liquid water is less than the Gibbs Free ...
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Room-conditions supercritical fluids?

Are there any reasonably obtainable supercritical fluids that I could, say, run my hand through? Wikipedia makes it sound like there are plenty of room-temperature ones, but no room-pressure fluids.
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Heat capacity during state change

I read that the heat capacity of water when it is at 100 °C or 0 °C is infinite because all the heat given to it will not be used to increase temperature but to change the state. I am unable to ...
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Why is CH4 a gas at room temperature but CH3Cl a liquid?

I cannot figure out a question on my review sheet. The full question is: Methane ($\ce{CH4}$) is a gas at room temperature but chloroform ($\ce{CH3Cl}$) is a liquid. Explain why changing just one $\...
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Which phase is more efficient for temperature changes?

In the case of attempting to heat and cool down an object of different states, if you in some case managed to achieve the same temperature of a solid, liquid and gas what state would scientifically ...