Boiling point Definition and 128 Threads

The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor.
The boiling point of a liquid varies depending upon the surrounding environmental pressure. A liquid in a partial vacuum has a lower boiling point than when that liquid is at atmospheric pressure. A liquid at high pressure has a higher boiling point than when that liquid is at atmospheric pressure. For example, water boils at 100 °C (212 °F) at sea level, but at 93.4 °C (200.1 °F) at 1,905 metres (6,250 ft) altitude. For a given pressure, different liquids will boil at different temperatures.
The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level, one atmosphere. At that temperature, the vapor pressure of the liquid becomes sufficient to overcome atmospheric pressure and allow bubbles of vapor to form inside the bulk of the liquid. The standard boiling point has been defined by IUPAC since 1982 as the temperature at which boiling occurs under a pressure of one bar.The heat of vaporization is the energy required to transform a given quantity (a mol, kg, pound, etc.) of a substance from a liquid into a gas at a given pressure (often atmospheric pressure).
Liquids may change to a vapor at temperatures below their boiling points through the process of evaporation. Evaporation is a surface phenomenon in which molecules located near the liquid's edge, not contained by enough liquid pressure on that side, escape into the surroundings as vapor. On the other hand, boiling is a process in which molecules anywhere in the liquid escape, resulting in the formation of vapor bubbles within the liquid.

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  1. neilparker62

    Explanation for high boiling point of Iodine Monobromide as compared to Iodine Monofluoride

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  2. SCHROEDERFPM

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  3. C

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  4. chemisthypnos

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  5. yecko

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  6. D

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  8. T

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  9. J

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

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  10. José Ricardo

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  11. Decimal

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  12. dromeascr

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  13. Z

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  14. D

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  15. A

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  16. Enigman

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  17. D

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  18. G

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  19. B

    How volatile impurity affects boiling point of a liquid?

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  20. A

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  21. R

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  22. S

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  23. D

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  24. T

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  25. T

    Highest boiling point between organic compounds

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  26. T

    Why does arsenic sublimate, while gallium melts?

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  27. Biker

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  28. S

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  29. A

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  30. A

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  31. C

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  32. T

    Which Compound Has Highest Boiling Point?

    Homework Statement Of the following compounds, which has the highest boiling point? (A) CH3—CH3(B) CH3—CH2OH(C) CH3—COOH(D) CH3—COH(E) H2S Homework Equations - The Attempt at a Solution Chose C because is more polar with the 2 oxygens, however, the answer has conflicting answer. It...
  33. S

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  34. T

    How do solute particles increase boiling point?

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  35. E

    Does Propanoic Acid Have a Lower Boiling Point Than n-Butyl Alcohol?

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  36. faiziqb12

    How does temperature affect distillation in a fractionating column?

    i have got a question with distillation . in distillation as we know the mixture is boiled and the mechanism then goes like substances with high boiling points condense at the bottom and substances with lower boiling points condense on the way to the top. i don't know why , but i am having...
  37. S

    How to calculate amount of vapor given q(t) and p(t)?

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  38. ScepticAmatuer

    Boiling point of water heated via microwave

    I took about 100 ml of distilled water, put a small, clean rock in it (to prevent "bumping" or explosion) and heated it repeatedly in a microwave oven on high for 45 seconds. After each heating I checked the temperature of the water with a digital temperature probe. I did this 7 or 8 times...
  39. L

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    Homework Statement When benzene freezes at 5.5 C its density changes from 0.879 g cm-3 to 0.891 g cm-3. Its enthalpy of fusion is 10.59 kJ mol -1. Estimate freezing point of benzene at 1000 atm Homework Equations Solid liquid boundary: p=p*+ΔHfus/ΔV ln(T/T*) The Attempt at a Solution From the...
  40. UMath1

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    In class, we did a lab to determine the boiling point of rubbing alcohol. We used a thiele tube filled with water and place a test tube attached to a thermometer w/rubber band in it. However, we never saw any signs of boiling. We conducted several trials, the temperature went all the way above...
  41. VoteSaxon

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  42. B

    Understanding Vapor Pressure in Open Systems

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  43. A

    Boiling point and vapour pressure

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  44. A

    Why do sugars have higher boiling points than water?

    I recently heard about an interesting chemistry experiment I have yet to try. It involves boiling soda and watching the water rise and the sugars remain at the bottom of the pot. The reason being is sugars have higher boiling points than water. Thus, the water boils first, heats up, and rises to...
  45. K

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  46. M

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  47. K

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  48. Q

    Boiling point of ethers and alkanes

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  49. S

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    Just a random question. Is there a specific relationship between density and boiling point? If there is, what is it and why do they relate?
  50. Y

    What Is the Boiling Point of POE Oil at 500 Microns Pressure?

    What may be the boiling point (temperature) of a refrigeration POE oil at, let's say, 500 microns absolute pressure ?
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