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Questions tagged [evaporation]

The process of a liquid changing to a gaseous state

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Does water need oxygen to evaporate?

For example, if you had a thick piece of glass and it had a kind of reservoir inside with half water and half space allowing the water to move but not escape from the inside of the glass, and then you ...
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can we create an artificial cloud by evaporating ground water?

I need a clarity about whether an artificial cloud can be made by human or not,if it is so, then it will be useful for many.
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On the evaporation of fluids

Q. In which portion (1,2,3) there will be maximum concentration of evaporated water droplets? Or there will be uniform distribution of droplets? Background: Today, I noticed something really strange ...
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How do salt crystals evaporate in water?

Salt dissolves in water but when water has evaporated it is still there. What has happened to the salt in the water and why is it still there when water has evaporated?
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Why did the liquid disappear from some unopened aluminum cans? My experience (read below) has not been answered [duplicate]

I’m posting my question because I read this original post. The post was from 2016, so I’m reposting in hopes that someone can answer. Here’s the original post: (Also, do not flag as duplicate. If you ...
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Water vapor pressure in oxygen bubble

Suppose we have a source of O$_2$ bubble formation in water at specific nucleation sites, how can we estimate the water vapor pressure inside the O$_2$ bubbles? I know that: (1): $p_\mathrm{O_2}+p_\...
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Relative humidity, definition and its dependence on state variables

Relative humidity ($RH$) is defined by the following equation: $$ RH = \frac{p_{vap}}{p_{sat}} $$ Where $p_{vap}$ is the vapour pressure and $p_{sat}$ is the saturation vapour pressure. VAPOUR ...
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Why does salt ions is not exist at vapor when the water is boiled and evaporated?

I would like to understand when the water is boiled only pure vapor is produced and ions do not exist with vapor. Why? Can't the ions stick to water vapor? And Are Na+ and Cl- have boiling points? ...
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Rate of direct (non-thermal) photon-induced evaporation of water?

I have read a long time ago of early experiments in the evaporation rate of surface water, and a discovery that in addition to the Sun's impact on the temperature of the water, it was believed that ...
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Evaporation rate of water with forced convection

A steel pot (diameter 200 mm) is fully filled with water (2 kg of water) and the water is maintained at a constant temperature of 40°C by supplying heat from an electrical tabletop burner. Assume ...
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Why do we sweat on a hot and humid day but the clothes are able to dry?

I know that on a humid day,water vapour content is high in air and as a result evaporation of sweat is lesser and hence we feel hotter. What I am not able to get is, if water vapour content is high,...
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Can we enhance evaporation rate with a vacuum pump?

First, consider having water at 100C and 1atm and a heat source. If more heat added to water, we have more evaporation rate according to the following formula: $$Q_{in}=m_{vapor}*h_{fg}$$ THEN ...
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Water at 0 atmospheric pressure

Suppose I put a bucket of water on the surface of the Earth. Then somehow the atmosphere disappears. My question is: Would the water fly out of the bucket, or would it be still there? My reasoning ...
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Amount of steam generated using gas burner and Induction cooker

I did an experiment by boiling water using two different heat sources. At first, I boiled water using a gas stove, then I repeated by using an induction cooker. I noticed that the amount of steam (...
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Effect of pressure when drying wet clothes in a windy environment

When we hang wet clothes outside, they dry faster if it is windy. The wind causes forced convection and removes the air saturated with vapor, and the rate of evaporation does not decrease much in ...
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Why perspiration drops are seen in shopping bag?

Why perspiration drops are seen in shopping bag? When i put hot bread in shopping bag after sometime i saw perspiration drops in the shopping bag.
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Will having two water pans in my smoker make any difference?

I have a backyard smoker, and I use a tray of water in it as thermal mass to help keep the temperature stable. I don't think the size of the tray is going to matter, but it's roughly 40cm x 30cm x ...
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Potential Energy of Particles

I read the following statement in my textbook While a liquid is boiling, the energy supplied to the liquid goes to breaking the bonds between neighbouring molecules. Can anyone explain the process ...
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What happens at the molecular level during evaporation?

During boiling the liquid gets its energy from the heat source so it can break the force between molecules and turn into gas while evaporation happens at the top of the liquid at any temperature. ...
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Does the presence of a flame affect the flow rate of gas out of a lighter or torch?

If I were to set a propane torch's valve to a fixed open position, would it run out of gas faster lit or unlit? Does the flame produce any kind of pressure change that affects the flow rate through ...
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Evaporation amount of water for a Storm [closed]

How much water from the ocean is evaporated for a storm over water? I am trying to figure out what conditions will cause the most evaporation or how to calculate the amount of water evaporated for a ...
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Can a substance have zero vapour pressure above absolute zero?

According to this Reddit thread, the answer is no, vapor pressure can't be zero when temperature is above absolute zero. I suspect the answer might actually be yes according to a precise definition I ...
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Will water in a vacuum evaporate continously?

Will a vacuum chamber that is maintained at 0.1 Atmospheres with an open water container inside ever reach 100% humidity of the remaining air, so that no more water evaporates or will water ...
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Simple question about molecules leaving a liquid at a temperature below the boiling point

My textbook asks the question why a liquid cools down when partial evaporation occurs just below the surface at a temperature below the boiling point. The answer is of course that only those ...
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Temperature Proxy (Climate)

At the bottom of the wikipedia article on climate proxies there is this formula: $$ \delta \, {\rm ^{18}O} = \frac{\frac{\left[\rm{^{18}O}\right]}{\left[\rm{^{16}O}\right]}}{\frac{\left[\rm{^{18}O}\...
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Calculating gas pressure following water transformation to vapor (in contact with boiling oil)

When water falls into a pot of boiling oil, it turns into vapor, and in an enclosed space this will create a higher gas pressure. Is there a way to figure out how high of a gas pressure there will be ...
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What type of heat is efficient to evaporate water?

I found that there are several type of heating element in a hair dryer, but basically I mainly classify them into two ways of heat transfer: Radiation and Conduction. The conventional hair dryer uses ...
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Why does evaporation cause cooling?

I am aware that the evaporation process causes cooling in the remaining liquid, but why? If anyone can give me the maths and or equations to prove / show this I would be most appreciative.
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Do solids do something analogous to liquids evaporating below their boiling point?

I'm probably not entirely right, but evaporation differs from boiling in that it is surface rather than bulk phenomenon driven by a pressure gradient rather than temperature. If a volume of liquid is ...
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Evaporative calculation

I have some questions on evaporative calculation. That is, if I have a solution at temperature A initially, and it was placed at an environment of temperature A as well. Due to evaporation, the ...
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Why do really cold objects evaporate really quick? [closed]

So I saw a video of LNG (liquid natural gas) and when it got in contact with water, which was room temp the LNG evaporated instantly...why? Ice takes a while to evaporate like a sec even when hot ...
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Rate of evaporation/mass loss of liquid in a bowl

Say a hemispherical bowl filled with a liquid was left in a room. I was wondering how we could model the rate of mass loss of liquid as it evaporates. Will it be a quadratic relationship with time? ...
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Does the saturated vapor pressure depend on the external pressure or just only temperature?

So far I understand that the saturated vapor pressure is the pressure exerted by a substance in liquid (or solid) vapor equilibrium, and that this pressure depends on the temperature of the system. ...
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Evaporation inside a container

This is for my engineering design project and our group needs to make a storage where humidity inside should be maintained above a certain range. So as a simple prototype, we simply added a bit of ...
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Can a droplet of formalin evaporate in midair while falling? [closed]

I am designing an evaporator for use in an enclosed environment. Due to the hazardous nature of formaldehyde, I want my evaporator to be wick-free. The environment in which the evaporator will be ...
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Interesting thought experiment on evaporation and pressure

Little background: the enthalpy of vaporization equals energy required to change state, plus the work done against ambient pressure. Say I made a balloon with Gore tex.(Gore tex is a fabric that ...
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Why are the wet patches on these floor tiles circular?

My friend's 3-year-old daughter asked "Why are there circles there?" It had either rained the night before or frost had thawed. What explains the circles? Follow-up question: Ideally, are these ...
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How can frozen clothes dry overnight?

I put some wet Polyester clothes outside for the night (the clothes were washed by hand with pretty cold water -maybe around 4°C- and wringed by hand so there was still water dropping of them when I ...
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Is it possible to explain evaporation using thermodynamics only?

I'm wondering whether it's possible to explain water evaporation using the theory of thermodynamics only, as opposed to the commonly cited statistical mechanics. Indeed, the usually given explanation ...
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How to calculate vaporization energy of water given a defined surface and liquid temperature?

One Stainless Steel container with inner diameter of 300mm Open system Ambient temperature 25 Celsius Water temperature is Regulated to 90 Celsius Assuming that we neglect energy lost by ...
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Why does water droplet change shape as it evaporates?

This .gif was posted on reddit /r/gifs, with title "A water droplet evaporating." I'm not actually sure if that is actually the case here. Regardless, if we were to look at the process we can see ...
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Are there materials with a negative enthalpy of vaporization?

I just answered a question about boiling water which concerned the vaporization enthalpy of water — the energy needed to evaporate it, ceteris paribus —, which is substantial. I was ...
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How do we compare the effect of air pressure and the effect of temperature, on evaporation?

Let's say we have some water with a boiling point of 90 Celcius in it's current environment; and with the same mass, same humidity, same bucket and all, we have some water with a boiling point of 100 ...
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Can I increase cooling efficiency with evaporative cooling?

I had an idea recently. But I don't have the physics knowledge to know if it makes sense or not. I've become a bit of a PC enthusiast lately and one thing that is big in the PC world lately is water ...
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Why don't liquids just boil off in the open just as they would in a vacuum?

I understand that all solids and liquids are unstable to vaporisation in vacuum (because some molecules will always have the energy to escape the bonds due to the nature of thermal energy distribution)...
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Purpose of coil in liquid propane torch

Many liquid propane torches (including burners for hot-air balloons) have coils placed in the line of fire heating the liquid before it reaches the nozzle. I am very puzzled by the exact function of ...
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What law or formula discusses the relationship between pressure and dew point?

A lot of times, dew point is focused primarily upon temperature and relative humidity. However, that same point of saturation is affected by the pressure, but I can't find a formula, or law even, that ...
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Is vapor pressure affected by dissolved gasses in the liquid?

If I take a half full bottle of water, seal it with a pressure gauge, and wait a few days then it will be at equilibrium. If I observe the pressure, that would be the water vapor's pressure. However, ...
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If I boil water at room temp using a vacuum, will the water instantly liquify if I reintroduce air to the system?

If I boil water at room temperature in a vessel using a vacuum pump, will the water instantly liquefy and fall back into a liquid pool if I reintroduce air into the system? Basically, if this is a ...
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Must gaseous water be 100C (or greater) regardless of pressure?

I know that if you evaporate a molecule of water, that it must be 100C in order to be gaseous, so that it will take that heat with it if it wasn't already that temperature. This has a cooling effect ...