为什么热空气"持有"更多的水分?- 江南体育网页版- - - - -地球科学堆江南电子竞技平台栈交换 最近30从www.hoelymoley.com 2023 - 04 - 06 - t22:58:21z //www.hoelymoley.com/feeds/question/15379 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/15379 16 为什么热空气"持有"更多的水分? 克拉克 //www.hoelymoley.com/users/14081 2018 - 10 - 18 - t11:58:31z 2023 - 01 - 17 t01:59:42z < p >通常解释说,温暖的空气中含有更多的水,因为温暖的水凝结的可能性较小。这和其他的解释似乎是循环论证。如果热空气拿起足够的水分将饱和水,然后仍将凝结在100%湿度。< / p > < p >给定两个立方英尺的空气与一个比另一个温暖温暖更多的水,水分子/如何所有这些额外的无形适合在温暖的立方英尺吗?什么是深会发生物理或化学原因? < / p > //www.hoelymoley.com/questions/15379/-/15380 # 15380 16 由BarocliniCplusplus回答为什么热空气"持有"更多的水分? BarocliniCplusplus //www.hoelymoley.com/users/704 2018 - 10 - 18 - t14:50:53z 2018 - 10 - 18 - t15:27:53z < p >说,热空气“持有”更多的水分在技术上是不正确的,但是是一种常见的口语。让我们将其分解技术。< / p > < p >让我们考虑一杯水和一个真空(没有空气)上面。会发生什么呢?最顶部的分子层的水会蒸发。以什么速度将水蒸发?更好的是,蒸发是什么?< / p > < p >蒸发是当水分子获得足够的动能(他们振动速度)将持有的债券。动能是依赖于温度。所以分子振动速度,打破他们的债券,并进入真空蒸汽。 Some molecules will stay as a vapor in the vacuum, but others will reenter the liquid. When the molecules enter the liquid as fast as they are leaving, then it is saturated.

If the air is cooled down, then the rate at which molecules leave the liquid slows down. The molecules entering the liquid do not slow down at the same rate, causing the liquid to grow toward it's initial state.

Note that I specifically said it is a vacuum. Instead of a glass of water, picture the water as little drops. The atmosphere can act to warm or cool these drops, and vice-versa.

In the more nitty-gritty aspect of this, the equation that describes the vapor pressure as a function of temperature is called the Clausius-Clapeyeron equation/relation. The American Meteorological Society has one approximate solution, but I prefer this equation: $$e_{sat}(T)=611 Pa \exp[\frac{L_v}{R_v}(273.15^{-1}-T^{-1})]$$, where $L_v$ is the latent heat of vaporization, $R_v$ is the specific gas constant for water vapor, and $T$ is the absolute temperature in Kelvin. Combined with the ideal gas law for water vapor (assuming saturation) $$e_{sat}(T)V=m_vR_vT$$, and given the volume ($V$) we can write an expression for the mass of water vapor $m_v$. The equation comes out to $$m_v=611 Pa \exp[\frac{L_v}{R_v}(273.15^{-1}-T^{-1})]V R_v^{-1}T^{-1}$$

To answer your final question, the molecules are approximated as being infintessimally small, per the ideal gas law. To be more specific, one molecule of water is about 7.08$\times$ 10$^{-19}$ cubic feet (after some math), so the added volume is considered negligible. In short, the molecules are treated as point masses.

//www.hoelymoley.com/questions/15379/-/15382 # 15382 6 回答大卫Hammen为什么热空气"持有"更多的水分? 大卫Hammen //www.hoelymoley.com/users/239 2018 - 10 - 18 - t16:21:22z 2018 - 10 - 18 - t16:21:22z < blockquote > < p >这个发生深刻的物理或化学的原因是什么?< / p > < /引用> < p >的一个词,熵。< / p > < p >(即在一千个单词。图),< / p > < p > < a href = " https://i.stack.imgur.com/o004H.png " rel = " noreferrer " > < img src = " https://i.stack.imgur.com/o004H.png " alt =“水的相图”> < / > < br > <子>来源:维基百科文章< a href = " https://en.wikipedia.org/wiki/Phase_diagram " rel = " noreferrer " >相图< / > < /订阅> < / p > <人力资源> < p >以上是水的相图。曲线之间的利益是蒸汽(棕色区域)和固体或液体(蓝色和绿色区域)。对于一个给定的温度(一条垂直线的图),它是由熵有利于水固体或液体当水蒸气的分压高于升华或蒸发曲线,但它是由熵有利于水蒸汽分压时以下曲线。< / p > < p >注意:感兴趣的压力是水蒸气的分压,没有空气的压力作为一个整体。另一方面,空气的温度是决定存在水蒸气的温度。还要注意:上面的图是平面。小水滴具有较高的表面张力,从而增加了有效的饱和压力在空气非常干净。例如,(这是为什么雪花几乎总是有一个小粒尘埃中心。)尽管如此,有效饱和压力遵循相同的形式:温度增加而增加。< / p > < p >你要求一个深奥的物理学原因为什么会这样。假设表面水冰或液体和水蒸气之间的平衡; i.e., the air is the saturated with water vapor. The water vapor molecules have a speed distribution approximately given by the Maxwell–Boltzmann distribution. Some water vapor molecules will be moving slower than others. Those slow-moving molecules that hit the surface are more likely to be absorbed by the surface than are those molecules that are moving faster. The molecules in the ice or liquid water are also vibrating / moving at different speeds. The fast moving solid/liquid water molecules are more likely to escape the surface than are those that are moving slower. Under equilibrium conditions, the rates at which vapor molecules are captured and ice/liquid molecules escape are equal.

Raising the temperature of the solid/liquid and of the vapor means fewer vapor molecules will be moving slow enough to be captured while more solid/liquid will be moving fast enough to escape. This increases the pressure at which equilibrium occurs. Lowering the temperature similarly decreases the pressure at which equilibrium occurs.

//www.hoelymoley.com/questions/15379/-/15386 # 15386 7 由rchuso回答为什么热空气"持有"更多的水分? rchuso //www.hoelymoley.com/users/6313 2018 - 10 - 18 - t22:20:11z 2018 - 10 - 18 - t22:20:11z < p >大气中的水分子只是另一个分子——除了它的三原子,而99.97%的干燥的大气是单原子(氩)和双原子(氧和氮)。也有点电极化,因此它有一个低能量状态时存在的类似的分子(液体或固体形态),和在更高的温度。< / p > < p >所以“为什么不所有空气的水蒸气直接掉出来吗?”What's keeping these molecules in the the vapor state is simply the energy of motion. Cool the atmosphere (remove this energy) and the water vapor will be allowed to return to its lower energy state. The same thing will happen with all the other atmospheric constituents - just at different temperatures and pressures.

//www.hoelymoley.com/questions/15379/-/24758 # 24758 0 由本·布莱克威尔回答为什么热空气"持有"更多的水分? 本·布莱克威尔 //www.hoelymoley.com/users/28317 2023 - 01 - 17 t01:59:42z 2023 - 01 - 17 t01:59:42z < p >如果你想量化水蒸气可以有多少空气干燥,对于一个给定的温度和相对湿度,您可以使用什么ASHRAE这样(美国采暖、制冷和空调工程师)一个湿度图。这个图表可以发现背后的理论在许多工程热力学文本。例如,“工程Thermodynamics"第二版,格伦·e·迈尔斯AMCHT出版物,2007。下面是一个副本的一个页面的文本。纵轴的情节是湿度比(磅的水蒸气/磅干燥的空气)。对于给定的相对湿度,温度湿度比单调。湿度比上升温度比直线更快速。< a href = " https://i.stack.imgur.com/Jo0yV.jpg " rel = " nofollow noreferrer " > < img src = " https://i.stack.imgur.com/Jo0yV.jpg " alt = "心理图表" / > < / > < / p >
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