14.12 道尔顿部分压力法

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  道尔顿局部压力法

  

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  Is there oxygen available on Venus?
  ::金星上有氧气吗?

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  The atmosphere of Venus is markedly different from that of Earth. The in the Venusian atmosphere are 96.5% carbon dioxide and 3% nitrogen. The on Venus is roughly 92 times that of Earth, so the amount of nitrogen on Venus would contribute a pressure well over 2700 mm Hg. And there is no oxygen present, so we couldn’t breathe there. Not that we would want to go to Venus – the surface temperature is usually over 460°C.
  ::金星的大气与地球的大气明显不同。金星大气中的二氧化碳和氮分别为96.5%和3 % 。 金星的大气是地球的92倍左右,因此金星的氮含量将产生超过2700毫米汞的压力。 并且没有氧气,因此我们无法在那里呼吸。 我们不想去维纳斯 — — 地表温度通常超过460摄氏度。

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  Dalton’s Law of Partial Pressures
  ::道尔顿局部压力法

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  results from collisions between gas particles and the inside walls of their container. If more gas is added to a rigid container, the gas pressure increases. The identities of the two gases do not matter. John Dalton, the English chemist who proposed the atomic theory , also studied mixtures of gases. He found that each gas in a exerts a pressure independently of every other gas in the mixture. For example, our atmosphere is composed of about 78% nitrogen and 21% oxygen, with smaller amounts of several other gases making up the rest. Since nitrogen makes up 78% of the gas particles in a given sample of air, it exerts 78% of the pressure. If the overall atmospheric pressure is 1.00 atm, then the pressure of just the nitrogen in the air is 0.78 atm. The pressure of the oxygen in the air is 0.21 atm.
  ::气体粒子及其容器内壁的碰撞是气体粒子和容器内壁碰撞的结果。 如果将更多的气体添加到硬容器中, 气体压力会增加。 这两种气体的身份并不重要。 提出原子理论的英国化学家约翰·道尔顿(John Dalton)也研究了气体的混合物。 他发现每种气体在一种气体中施加的压力与混合物中的其他气体不同。 例如, 我们的大气层由大约78%的氮和21%的氧组成, 其余的由少量的其他气体组成。 由于氮在特定空气样本中占气体颗粒的78%, 它施加了78%的压力。 如果整个大气压力为1. 00 时, 那么空气中仅仅氮的压力是0.78 时。 空气中的氧气压力是0.21 时。

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  The partial pressure of a gas is the contribution that gas makes to the total pressure when the gas is part of a mixture. The partial pressure of a gas is indicated by a  $\begin{array}{r}P\end{array}$ with a subscript that is the symbol or formula of that gas. The partial pressure of nitrogen is represented by  $\begin{array}{r}{P}_{N_2}\end{array}$ . Dalton’s law of partial pressures states that the total pressure of a mixture of gases is equal to the sum of all of the partial pressures of the component gases. Dalton’s law can be expressed with the following equation:
  ::气体的部分压力是指当气体是混合物的一部分时气体对总压力的贡献。气体的部分压力由P表示,其下标是该气体的符号或公式。氮的部分压力由PP表示。氮的部分压力由PN2表示。Dalton的部分压力法规定,气体混合物的总压力等于成分气体所有部分压力的总压力的总和。Dalton的法律可以用下列公式表示:

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  $$\begin{array}{r}{P}_{\text{total}}=P_1+P_2+P_3+\dots \end{array}$$

  
  ::总计=P1+P2+P3+...

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  Figure shows two gases that are in separate containers of equal volume at the same temperature. Each exerts a different pressure,  $\begin{array}{r}{P}_1\end{array}$ and $\begin{array}{r}{P}_2\end{array}$ , reflective of the number of particles in the container. On the right, the two gases are combined into the same container, with no change in volume or temperature. The total pressure of the gas mixture is equal to the sum of the individual pressures. If $\begin{array}{r}{P}_1=300\text{ mmHg}\end{array}$ and $\begin{array}{r}{P}_2=500\text{ mmHg}\end{array}$ , then $\begin{array}{r}{P}_{\text{Total}}=800\text{ mmHg}\end{array}$ .
  ::图中显示了在相同温度下不同体积的容器中的两种气体,每种气体施加不同的压力,即P1和P2,反映容器中的颗粒数量。在右边,两种气体混入同一个容器,体积或温度不变。气体混合物的总压力等于个别压力的总和。如果P1=300毫米Hg和P2=500毫米Hg,那么PTol=800毫米Hg。

  

   

   

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  Summary
  ::摘要

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  • The total pressure in a system is equal to the sums of the partial pressures of the gases present.
    ::系统中的总压力等于所存在的气体部分压力的总和。

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  Review
  ::回顾

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  1. What is the foundation for Dalton’s law?
     ::道尔顿法律的基础是什么?
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  2. Argon makes up about 0.93% of our atmosphere. If the atmospheric pressure is 760 mm Hg, what is the pressure contributed by argon?
     ::Argon占我们大气的0.93%左右,如果大气压力为760毫米汞,则ARgon造成的压力是什么?
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  3. On a given day, the water vapor in the air is 2.5%. If the partial pressure of the vapor is 19.4 mm Hg, what is the atmospheric pressure?
     ::在某一天,空气中的水蒸气为2.5%。如果蒸气的部分压力是19.4毫米汞,那么大气压力是什么?