What is Boiling: Definition and 319 Discussions

Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the temperature at which the vapour pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmosphere. At sea level the boiling
point of water is 100 °C or 212 °F but at higher altitudes it drops to correspond with decreasing atmospheric pressures.
Boiling water is used as a method of making it potable by killing microbes and viruses that may be present. The sensitivity of different micro-organisms to heat varies. But if water is held at 100 °C (212 °F) for one minute, most micro-organisms and viruses are inactivated. Ten minutes at a temperature of 70 °C (158 °F) is also sufficient for most bacteria.
Boiling water is also used in several cooking methods including boiling, steaming and poaching.

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  1. H

    Boiling Water Sounds: Exploring What's Going On

    I boil water in a tea kettle. When it's starting to boil there are pinging sounds. These grow louder until there is some sort of phase transition and they quiet down. That's about when the tea kettle starts to whistle. What's going on?
  2. kyphysics

    After Dissolving Salt in Boiling Water, How Do You Get it Back?

    in solid form (the salt that is)? I had to try to answer this question for my 14 y/o cousin and think I may have messed it up. Good thing she knows I suck at science and to ASK HER TEACHER next time! :smile: Anyways, it got me curious. . .I first thought of just reversing the process. Since...
  3. pve

    Time to evaporate LN2 from a container

    Hello, Could someone please help me understand how to approximate how long it will take for liquid nitrogen in a room temperature container to completely evaporate. Here's the scenario: I have a metal container (41x13x15") filled with 5.5" of liquid nitrogen (just released from a Dewar ~ 320F)...
  4. C

    Do you need to account for the water heating up to the boiling point?

    High School Physics Lab: Take 200mL of water (Room temp) and place it in a microwave on high for 60 seconds. Calculate the Energy transferred to the water by the microwave. Pretty easy: Step 1: Heat of Temp Change : Q= mC∆T where m=200mL Step 2: Add Heat due to phase change: Q=mL where m=...
  5. H

    How can I save gas when boiling water on my gas stove?

    Every morning I boil two eggs for ten minutes. My gas canister emptied faster than I thought it would. Now I had noticed that most of the air heated by the gas never touches the pot. I had another burner with half the diameter of the one I had been using. That means 1/4 the circumference...
  6. chemisthypnos

    Searching for Low Impact Fluid with Boiling Point of 150-180 F

    I am looking for a good working fluid whose boiling point is in the range of 150-180 F for a waste heat recovery system. The fluid should be minimally flammable, preferably nontoxic, and low in environmental impact. Does anyone know of any working fluids that match this description?
  7. Physics Slayer

    Boiling a glass of water in a bowl of water - tricky question?

    I think the water in the bowl of water will boil first because the glass won't conduct the heat instantaneously, and hence the water in the glass will boil after the water in the bowl. Is this correct? I am guessing this is a trick question and the water in both boil at the same time, but I...
  8. K

    B Cheapest equipment to boil water at 60℃

    Water (any liquid) in a closed container boils when the vapor pressure of water (a property that depends on its temperature) equals the surrounding pressure. The vapor pressure of water at 60℃ is about ##1.99\times10^{4}## which is roughly 150 mm Hg.This principle is so simple, and yet, it is...
  9. hartmais

    A Can Raoult's Law Determine Boiling Points of Fuel Oil?

    Fuel oil like heavy fuel oil consists of multiple different Carbon and Hydrogen molecule strains. This means that there are a multiple of different boiling points with in the same oil. Cavitation in pumps and valves happen when due to the acceleration of the fluid the pressure drop causing the...
  10. yecko

    Vaporization latent heat vs boiling point

    answer is 78oCdelta G = delta H - T delta S -235,310- (-277,690) = -38.56e3- T (282.59-160.70) T = -664K I am not sure if my concept is correct. May anyone help a little bit on that please? thank you
  11. I

    Chemistry Melting and boiling points of titanium tetrahalides

    Table boiling point (°C) melting point (°C) TiF4 284 N/A TiCl4 -24 136.5 TiBr4 38 233.5 TiI4 155 377 The solution says that TiF4 is an ionic compound, while TiCl4, TiBr4, and TiI4 are covalent compounds. How would I determine this from the problem without prior...
  12. I

    Chemistry Structural isomer boiling points

    Why does the isomer C-C-C-N have the highest boiling point, rather than CC(N)C (where the N is attached to the second carbon)? Isn't N able to form 3 H-bonds in both cases? Thanks.
  13. KrisOhn

    Boiling Water using Heat vs. Vacuum

    If you bring a pot of water to boil, you will notice that the bubbles form on the bottom surface of the pot. This seems to make sense intuitively as this is the hottest surface, so this would be where the boiling action starts. When I was in school during a thermo lab we pulled a vacuum in a...
  14. H

    Boiling Tap Water for Drinking: Benefits & Risks

    Recently I have been boiling tap water, for about 30 minutes, everyday for drinking water. The reason I do it is because I don't like the taste of chlorimines and chlorine and this is the only way I know to get rid of them without also losing minerals. It works great, and in fact, the water...
  15. yecko

    Vapor-compression refrigeration system - boiling & critical point

    Is it the lower the boiling point the better? As room pressure and temperature already can change the phase without working at vacuum? And the higher critical point means it is hard to reach super critical phase? But there is transcritical CO2 cycle, which the critical point is so low, and...
  16. F

    Boiling & Critical Temperature: Understanding The Difference

    Are boiling temperature and critical temperature the same or they are different things?
  17. docnet

    Calculating Boiling Point of a Solution: A Joke Problem for Extra Credit

    The professor posted a take-home problem for us to solve for extra credit. Extra credit problem: Using nothing but pen, paper and a ham, calculate the boiling point of 1:1:1 solution of benzene, pentane, and ethylene in a pressurized tank filled with neon at 6 atm pressure. The Answer must be...
  18. il postino

    Chemistry Calculate the boiling temperature of methanol from thermodynamic data

    Calculate the boiling temperature of methanol at 60 atm knowing that Tc = 513K, Pc = 78 atm and the acentricity is 0.555. I would like you to help me start the exercise. I thought about using the Pitzer Correlation to be able to calculate the fugacity coefficient, but I don't have the...
  19. T

    Is cavitation worse at depth? (Fluid pressure and Vapor pressure boiling)

    I am wondering about the impact of the hydro static pressure of a fluid on its boiling point. The simplest real world example scenario I can think of is the rate/onset of cavitation at a large depth vs a shallow depth. As we increase the submarine propellor speed to a speed where the adjacent...
  20. P

    Boiling off Liquid Argon Using A High Powered Resistor

    I understand that liquid argon is constantly boiling when it's in contact with the air in the lab, but I want to increase that boil off rate. Because of that, I got myself a high powered resistor (1 ohm, 100 W) and got the highest current power supply I had (5A). When I supply about 5 V and 5 A...
  21. J

    Adding xylitol to hot water lowers the boiling point and makes it boil

    This probably occurs with salt too but let's concentrate on xylitol: you heat water till it boils, put the hot water in a cup and add a tsp of xylitol. It boils again violently for a couple of seconds. The high school explanation is that the boiling point of the water is lowered. I'd like to...
  22. C

    Does temperature increase when water is boiling at 100C......

    Does temperature increase when water is boiling at 100C in a closed system? I am picturing a scenario where I am boiling water in a pot to make pasta. However, I decide to close the pot as the water is still boiling. By doing this I am sealing away the system of study from the environment. Thus...
  23. J

    Pressure & Boiling: Exploring Relationship & My Understanding

    Hi everyone, I have been mulling over the relationship between pressure and boiling for some time, and I am still slightly confused. I shall attempt to provide an overview of my current understanding in the hope that I can get some corrections/clarification on my current conceptual...
  24. Death eater

    When boiling water, what is the degree of freedom inside the vapour dome?

    When water converts to steam while boiling a vapour dome can be formed, what is the degree of freedom inside this vapour dome and on the saturated points?
  25. D

    Boiling fluoride thorium reactor

    Some polymeric intermetallic pentaflouride have boiling points around 200+°C. Can an LFTR be build like a low pressure BWR while maintaining comparable efficiency under lower operating temperature?
  26. A

    How to calculate change in pressure from LN2 phase change

    I am trying to calculate the increase in pressure caused by liquid nitrogen when it changes from liquid to vapor within a closed, constant volume at atmospheric pressure. How can this be done? Do I need to include the heat of vaporization?
  27. José Ricardo

    Boiling point and connection distance of the elements

    Homework Statement Explain the following order of the boiling point (° C) HF (19.5)> HCl (-85.1) <HBr (-66.8) <HI (-35.4) b) Explain the following order of connection distance (pm): HF (92) <HCl (127) <HBr (141) <HI (161) Homework Equations xxx The Attempt at a Solution a) HF does hydrogen...
  28. Decimal

    Relation between temperature and boiling point?

    Hello, I am encountering some confusion with the relation between the latent heat of vaporization and the temperature of a substance. I understand both the latent heat and the entropy change of vaporization are dependent on the temperature, assuming the pressure is held constant. However given...
  29. T

    Why doesn't the temperature of water slightly decrease during boiling?

    When you heat a pot of water why wouldn't the water temp decrease slightly when it starts boiling? Isnt boiling a type of evaporation? In evaporation the molecules near surface have enough KE to escape into the gas phase, which then lowers the T of the remaining liquid. That is how sweating...
  30. Z

    Why is the boiling point of 2-propanol lower than 1-propanol

    Homework Statement Why is the boiling point of 2-propanol lower than 1-propanol? The Attempt at a Solution Is this right? Because 2-propanol has its hydroxyl group in the middle of the atom, the electrons are all moving to the centre of the atom as opposed to 1-propanol, which has the...
  31. D

    Effect of impurities on the boiling point of ethyl ethanoate

    After carrying out reflux and distillation to produce ethyl ethanoate (ethyl acetate) I measured the boiling point and I got 71 degrees Celsius whereas the true value is 77.1 degrees Celsius. Impurities increase the Boiling point (BP) as well as concentration. However my calculates BP is lower...
  32. P

    Why does liquid argon stop boiling after a while in dewar?

    When we fill a dewar or any other container with liquid argon (or liquid nitrogen), if I am correct, it sizzles because it is boiling. However, after we leave it inside for a few minutes, it stops. Does this happen because when you first pour it inside, the environment is of the liquid is much...
  33. EEristavi

    I Liquid boiling and Evaporation

    In the normal conditions (sea level) water evaporates at 100 C. In thermodynamics, we say: the amount of energy Q, can raise temperature of the liquid by the formula Q1=cm(t2-t1); when the liquid reaches the boiling point (100 C), we write Q2=Lm. Q2 is entirely spent on changing liquid state...
  34. A

    Effect of a soluble volatile impurity on the boiling point?

    Hi everyone, just wanted to know how does a soluble, volatile impurity affect the boiling point of a liquid? I know it depends on the difference between the boiling points of the liquid and the impurity, but I'm afraid i still didn't get the point. Thanks
  35. M

    Graduate level two phase flow boiling textbook

    I am looking for a graduate level textbook that would sufficiently describe the two phase flow characteristics during flow boiling. What textbook could I use to explore this topic? Is a graduate level forced convection going to cover two phase flow?
  36. V

    Help to determine convection coeficent or temperatures

    Homework Statement This is more like a design problem, I'm to evaporate water at 20°C and 2000 psi(Tsat=335.472°C), I have the heat flux the water is going to absorb during heating, and If that flux remains constant during all the length then, how can I find the surface temperature for the...
  37. Enigman

    Looking for a low boiling point solvent for MAPI precursors

    Things I have thought of till now: Acetonitrile with HI additive Acetonitrile with DMSO additive The problem with the first would be that HI is in an around 55% aqueous solution and water doesn't play well with the perovskite. Meanwhile, the second might end up needing enough DMSO to...
  38. Vital

    What happened to the boiling water

    Hello! This question is not about a particular homework exercise, or any exercise, but rather an astonishing real life fact, which I just experienced, and, as I am still on my way to becoming educated in science, I would like to ask for your help on how to explain this phenomena. I had a...
  39. J

    Would this device(pic inside) work for boiling cold water?

    Imagine some giant glass(or other material) dome placed on top of some ocean or lake. Then pump some air out of this dome, until the water level rises a few meters under the dome. Place another dome below the first dome, and repeat the process, resulting in a little less pressure in the second...
  40. A

    Simple distillation of compounds with similar boiling points

    I just had a lab, and the results really aren't adding up to what i expected. And this is specifically about simple distillation, not fractional distillation. Lets say i have a solution of two liquids, one's boiling point is 90°C and the other is 110°C, a 20°C difference which is pretty close...
  41. M

    Most efficient temperature to evaporate water?

    Hello, I have a question for you guys and gals. I am working on a Desalination project and am ironing out questions about efficiency. What would be the most efficient temperature to evaporate water? 50, 100, 110 degrees? Does it make a difference, or is the energy required to evaporate a fixed...
  42. D

    Exploring the Effects of Vacuum Pressure on Boiling Oil | Dilip

    Hi, We have seen water boiling at low pressures (vacuum jars), Will Oil also boil the same way in vacuum jar? Dilip
  43. G

    Resources for finding boiling point at other than 1 atm?

    I would appreciate it if someone could recommend something. I found a boiling point calculator by CalcTool but it doesn't seem that reliable.
  44. N

    Synthesis with a boiling toluene

    Hello everyone in a synthesis, they mixed oleylamine with a boiling solution of toluene for 2hours they didn't mention if it's with reflux or not ! i don't know if it doesn't represent any harmful consequence even in fume hood
  45. B

    How volatile impurity affects boiling point of a liquid?

    I know that non volatile impurities increases the boiling point of a liquid. Does volatile impurity decreases the boiling point? How?
  46. A

    Effect of particle size on boiling point in solution

    Hello. Suppose you dissolve something in water. I know that the boiling point should increase because as the water boils the solute's entropy decreases, and the net entropy should increase. Now suppose, that I dissolve GI chlorides in the water. Each solution of the salt has the concentration...
  47. Grayman

    Carbonated Water Freezing and boiling points

    Is there a way to calculate the freezing and boiling point of water that has different levels of CO2 in it?
  48. S

    Esters' high boiling point

    Why does 3-methylbutyl ethanoate have a higher boiling point than 3-methylbutan-1-ol and ethanoic acid? Attempt at a solution: I know that the ester has a marginally greater molar mass but I wasn't sure if this is the only deciding factor, particularly considering the strength of the other...
  49. A

    Heat energy and liquid nitrogen boil-off rate

    Homework Statement Kindly refer to part (c). The woking should be power/0.35 (what I think according to the graph). But the answer is power (that is the answer of part b) divided by 0.02 Homework Equations I have used the ratio method simply The Attempt at a Solution According to part (b)...
  50. O

    Evaluating my experiment; kettle water boiling efficiency

    Homework Statement Evaluate the experiment below, identifying energy loss and errors, and access their effect on the efficiency? The experiment was 'Determining the efficiency of energy conversion of boiling water in an electric kettle'. The method/system - 1. Weigh accurately 1000g of water...