Name: gas mixtures and their partial pressures
Uploaded: 2023-09-18T17:11:17.000Z
Duration: 1 min 11 s
Channel: JoVE

容器の中にガスがあるとします。ガスによって加えられる圧力は、その分子と周囲の表面との間の分子衝突によって加えられる力の合計です。
分子の数が多い気体は、同じ容器内の分子数が少ない気体よりも高い圧力がかかります。したがって、個々のコンポーネントからの圧力は、その分圧と呼ばれます。
熱平衡状態の容器内の理想気体の混合物を考えてみましょう。容器内の全圧力は、そのコンポーネントの分圧の合計に等しくなります。この観測は、ダルトンの分圧の法則として知られています。
理想気体方程式を思い出し、個々の気体の分圧を代入すると、全圧を決定できます。
同じ物質の液相と平衡状態にある蒸気の分圧は、蒸気圧と呼ばれます。
ある温度での水蒸気の分圧と水蒸気の蒸気圧の比は、相対湿度として知られています。

<ol>
	<li>OpenStaxです。(2019). 大学物理学 Vol.2.[Web版]、37〜38ページ。<a href="https://openstax.org/books/university-physics-volume-2/pages/2-2-pressure-temperature-and-rms-speed" から取得>https://openstax.org/books/university-physics-volume-2/pages/2-2-pressure-temperature-and-rms-speed</a></li>
</ol>

ドルトンの分圧の法則

Dalton's Law of Partial Pressure

ガスの分圧は、ガス分子の熱力学的活動の尺度です。 気体が利用可能な総体積を占める場合に発生する圧力は、気体の分圧と呼ばれます。 2 つ以上のガスが容器内で混合されると、分子はランダムに移動して互いに衝突し、熱平衡に達します。 気体の温度が同じであれば、それらの分子の平均運動エネルギーは同じになります。 したがって、各気体は理想気体の法則に個別に従い、容器の壁に同じ圧力を個別に及ぼします。 したがって、ガスの混合物では、理想的なガスの挙動と成分間に化学反応がないと仮定すると、コンテナ内の全圧力は成分ガスの分圧の合計になります。 この法則は、ドルトンの分圧の法則として知られています。 この理論は英国の科学者ジョン・ドルトン（1766–1844）によって確立されました。 ドルトンの法則は、パスカルの原理によると、圧力が加算されるという事実と一致しています。 熱平衡にある理想気体の混合物では、各気体の分子数はその分圧に比例します。

分圧のもう 1 つの重要な用途は蒸気圧です。これは、同じ物質の液相と平衡にある蒸気の分圧です。 どのような温度であっても、空気中の水の分圧はその温度での水の蒸気圧を超えることはできません。分圧が蒸気圧に達すると空気中の水が凝縮するからです。 結露はこの結露の一例です。 空気サンプルで凝結が発生する温度は露点と呼ばれます。 金属球をゆっくり冷却することで簡単に測定できます。 露点は、ボールに最初に結露が現れる温度です。

ガスの分圧は、ガスの分子の熱力学的活動の尺度です。ガスが占有した場合に発生する圧力...

Education

JoVE Core

Physics

物理学

Unit 1

ユニット1

The Kinetic Theory of Gases

気体分子運動論

KEY TERMS AND CONCEPTS

主要用語と概念

gas mixtures and their partial pressures

Gas mixtures have a total pressure that comes from the partial pressures of each gas. A partial pressure is the pressure one gas would make if it filled the whole container by itself. This idea helps explain how gases behave when they are mixed together.

When two or more gases share a container, their molecules move randomly and collide with one another. If the gases are at the same temperature, they reach thermal equilibrium. Their molecules then have the same average kinetic energy. In that case, each gas follows the ideal gas law separately and pushes on the walls of the container on its own.

The total pressure in the container is the sum of the partial pressures of the component gases. This result is called Dalton's law of partial pressures. It applies when the gases behave like ideal gases and do not react chemically with one another. The law was developed by the English scientist John Dalton, who lived from 1766 to 1844. It also agrees with Pascal's principle, which says that pressures add up.

Partial pressure also helps describe vapor pressure. Vapor pressure is the partial pressure of a vapor when it is in equilibrium with the liquid form of the same substance. In air, the partial pressure of water cannot rise above the vapor pressure of water at that temperature. If it reaches that value, water condenses out of the air. Dew is one common example of this process.

The temperature where condensation begins in a sample of air is called the dew point. One simple way to measure it is to cool a metal ball slowly. The dew point is the temperature at which condensation first appears on the ball.

Gas Mixtures and Their Partial Pressures

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key terms and concepts

Learn how gas mixtures share pressure through partial pressures, how Dalton's law works, and how vapor pressure and dew point explain condensation in air.

Gas Mixtures and Their Partial Pressures | JoVE K12

physics

JoVE Core 物理学は、運動学、力学、流体力学、静力学、波動、音響などの基礎的な物理学の理論と応用を、簡潔でわかりやすいアニメーション ビデオで紹介します。さらに、科学者の実際のビデオでは、世界中の今日の研究所で行われている古典的および独自の研究実験における関連概念の適用を示しています。

Gas Mixtures and Their Partial Pressures

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