What is Vaporisation: Definition and 14 Discussions

Vaporization (or vaporisation) of an element or compound is a phase transition from the liquid phase to vapor. There are two types of vaporization: evaporation and boiling. Evaporation is a surface phenomenon, whereas boiling is a bulk phenomenon.

Evaporation is a phase transition from the liquid phase to vapour (a state of substance below critical temperature) that occurs at temperatures below the boiling temperature at a given pressure. Evaporation occurs on the surface. Evaporation only occurs when the partial pressure of vapor of a substance is less than the equilibrium vapor pressure. For example, due to constantly decreasing pressures, vapor pumped out of a solution will eventually leave behind a cryogenic liquid.
Boiling is also a phase transition from the liquid phase to gas phase, but boiling is the formation of vapor as bubbles of vapor below the surface of the liquid. Boiling occurs when the equilibrium vapor pressure of the substance is greater than or equal to the environmental pressure. The temperature at which boiling occurs is the boiling temperature, or boiling point. The boiling point varies with the pressure of the environment.
Sublimation is a direct phase transition from the solid phase to the gas phase, skipping the intermediate liquid phase. Because it does not involve the liquid phase, it is not a form of vaporization.
The term vaporization has also been used in a colloquial or hyperbolic way to refer to the physical destruction of an object that is exposed to intense heat or explosive force, where the object is actually blasted into small pieces rather than literally converted to gaseous form. Examples of this usage include the "vaporization" of the uninhabited Marshall Island of Elugelab in the 1952 Ivy Mike thermonuclear test.At the moment of a large enough meteor or comet impact, bolide detonation, a nuclear fission, thermonuclear fusion, or theoretical antimatter weapon detonation, a flux of so many gamma ray, x-ray, ultraviolet, visual light and heat photons strikes matter in a such brief amount of time (a great number of high-energy photons, many overlapping in the same physical space) that all molecules lose their atomic bonds and "fly apart". All atoms lose their electron shells and become positively charged ions, in turn emitting photons of a slightly lower energy than they had absorbed. All such matter becomes a gas of nuclei and electrons which rise into the air due to the extremely high temperature or bond to each other as they cool. The matter vaporized this way is immediately a plasma in a state of maximum entropy and this state steadily reduces via the factor of passing time due to natural processes in the biosphere and the effects of physics at normal temperatures and pressures.
A similar process occurs during ultrashort pulse Laser ablation, where the high flux of incoming electromagnetic radiation strips the target material's surface of electrons, leaving positively charged atoms which undergo a coulomb explosion.

View More On Wikipedia.org
  1. B

    Finding latent heat of vaporisation

    Can anyone please help me on how to tackle this question? I really do not have any clue to make a start on it? Thanks for any help!
  2. D

    Entropy of Vaporization Calculation for 5 Moles of Argon at 87.5 K and 150 K

    Homework Statement 5 moles of liquid argon undergoes vaporization at its normal boiling point (87.5 K) and the resulting argon gas is subsequently heated to 150 K under constant volume conditions. Calculate the change of entropy for this process. The standard enthalpy change of vaporization, ∆...
  3. T

    Derivation: Entropy of Vaporisation using Redlich-Kwong EoS

    Homework Statement For some reason it is not letting me add the image here, here is the link to the question: http://imgur.com/a/3DLWM The part I'm stuck on is the last part. Basically, the question is to obtain the following equation for the entropy of vaporisation using the Redlich-Kwong...
  4. R

    Why is vaporisation rate increased by a decrease in pressure

    In my textbook, it says that the rate of vaporisation can be increased by (a) increasing the temperature or (b) reducing the pressure. I understand why an increase in temp can lead to more molecules breaking away from the liquid and entering the vapor state. More temp = more energy = more...
  5. T

    Why the temperature remains constant at the boiling point?

    Why all liquids vaporize on boiling point instead of the temperature gradually increasing along with vapor pressure and more liquid atoms evaporating? Does it have anything to do with formation of vapor bubbles?
  6. J

    Why specific latent heat of vaporisation > fusion?

    1. Homework Statement Homework Equations First law of thermodynamics, ΔU=q+W The Attempt at a Solution Ok so, I know that when liquid evaporates, the change in volume is much greater than that when solid melts. And for both cases, distance of separation of atoms increases too, so PE...
  7. T

    Is Vaporising Someone Considered Murder?

    1. Considering that not too many people have been vaporised, would you say it is murder?2. Because they are not alive anymore, does that necessarily mean they are dead? Forgetting religion, would you say having every single atom in your body separated would be death? Or Inanimation? I don't want...
  8. D

    Vaporisation of Water at different altitudes

    Hey All, I am undertaking an experiment for a final report for a physics course at university. I have chosen to study the boiling point of water at a range of different pressures as a result of different altitudes. I am using the Clausius-Clapeyron relation after obtaining the boiling point...
  9. Saitama

    Finding latent heat of vaporisation as a function of temperature

    Homework Statement The vapour pressure of a certain liquid is given by the equation: \log_{10}P=3.54595-\frac{313.7}{T}+1.40655\log_{10}T where ##P## is the vapour pressure in mm and T is temperature in kelvin. Determine the molar latent heat of vapourisation as a function of temperature...
  10. L

    Latent heat of vaporisation question

    Homework Statement A pupil performing an experiment finds that, when the heat supply is 16W, it takes 30 mins for the temp of the water to rise from 20°C to 100°C, and that the rate of evap is very slow even at the latter temp. Estimate an upper limit to the value of the heat capacity of the...
  11. M

    Vaporisation of coffee in a sealed cup

    Just wondering - if you have one of those cups of coffee with a lid on it, how much of the liquid would evaporate (assuming reasonable figures for the size of the cup and temperature of the liquid or whatever other variables are relevant)? Since it's essentially a sealed container, I'd assume...
  12. B

    Where Does the Energy Go When a Ball Becomes Embedded?

    Ive got this question but i don't know how to answer it. A steam boiler produces steam at a rate of 0.5 kg.s-1. If the specific latent heat of vaporisation of water is 2.3 MJ kg-1: (a) What power is consumed to achieve this rate? cheers
  13. B

    Heat of vaporisation help please

    Hi, i am writing a assignment about thermal expansion and contraction and i would like to know if anyone could explain to me why the heat of vaporisation is nearly seven times that of the heat of fusion for water. I thought it might be hydrogen bonding but this is present in both the liquid and...
  14. R

    Calculating Rate of Vaporisation: 240 W Body Heat Loss

    Homework Statement During exercise the body loses 240 W of heat due to the evaporation of sweat. Assuming that the latent heat of at body temprature is 2255 kJ/kg, determine the rate of vaporisation of sweat. answer = 106 mg/s Homework Equations L=Q/m The Attempt at a Solution...