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

ضع في اعتبارك غاز داخل حاوية. الضغط الذي يمارسه الغاز هو مجموع القوى التي تمارس بسبب الاصطدامات الجزيئية بين جزيئاته والسطح المحيط.
يمارس الغاز الذي يحتوي على العديد من الجزيئات ضغطا أعلى من الغاز الذي يحتوي على عدد أقل من الجزيئات في نفس الحاوية. لذلك ، يسمى الضغط من المكون الفردي بضغطه الجزئي.
ضع في اعتبارك مزيجا من الغازات المثالية في وعاء عند التوازن الحراري. الضغط الكلي داخل الحاوية يساوي مجموع الضغوط الجزئية لمكوناتها. تعرف هذه الملاحظة باسم قانون دالتون للضغوط الجزئية.
بتذكر معادلة الغاز المثالية واستبدال الضغوط الجزئية للغازات الفردية ، يمكن تحديد الضغط الكلي.
يسمى الضغط الجزئي للبخار الذي يكون في حالة توازن مع الطور السائل لنفس المادة بضغط البخار.
تعرف نسبة الضغط الجزئي لبخار الماء إلى ضغط بخار الماء عند درجة الحرارة بالرطوبة النسبية.

<ol>
	<li>OpenStax. (2019). جامعة الفيزياء المجلد 2. [نسخة الويب] ، الصفحة 37 - 38. تم الاسترجاع من <a href="https://openstax.org/books/university-physics-volume-2/pages/2-2-pressure-temperature-and-rms-speed">https://openstax.org/books/university-physics-volume-2/pages/2-2-pressure-temperature-and-rms-speed</a></li>
</ol>

قانون دالتون للضغط الجزئي

Dalton's Law of Partial Pressure

<div style="direction:rtl">الضغط الجزئي للغاز هو مقياس للنشاط الديناميكي الحراري لجزيئات الغاز. يسمى الضغط الذي قد يحدثه الغاز إذا احتل الحجم الإجمالي المتاح بالضغط الجزئي للغاز. إذا تم خلط غازين أو أكثر معًا في وعاء، فإن الجزيئات تتحرك عشوائيًا وتتصادم مع بعضها البعض، مما يؤدي إلى وصولها إلى التوازن الحراري. عندما تكون للغازات نفس درجة الحرارة، يكون لجزيئاتها نفس متوسط الطاقة الحركية. وبالتالي، يخضع كل غاز لقانون الغاز المثالي بشكل منفصل، ويمارس نفس الضغط على جدران الحاوية بشكل فردي. لذلك، في خليط الغازات، يكون الضغط الإجمالي في الحاوية هو مجموع الضغوط الجزئية للغازات المكونة، بافتراض سلوك الغاز المثالي وعدم وجود تفاعلات كيميائية بين المكونات. يُعرف هذا القانون بقانون دالتون للضغوط الجزئية. تم تأسيس النظرية من قبل العالم الإنجليزي جون دالتون (1766-1844). يتوافق قانون دالتون مع حقيقة أن الضغوط تتراكم وفقًا لمبدأ باسكال. في خليط الغازات المثالية في حالة توازن حراري يتناسب عدد جزيئات كل غاز مع ضغطه الجزئي. تطبيق آخر مهم للضغط الجزئي هو ضغط البخار، وهو الضغط الجزئي للبخار الذي يكون عنده في حالة توازن مع الطور السائل لنفس المادة. عند أي درجة حرارة، لا يمكن أن يتجاوز الضغط الجزئي للماء في الهواء ضغط بخار الماء عند درجة الحرارة تلك، حيث أنه كلما وصل الضغط الجزئي إلى ضغط البخار، يتكثف الماء خارج الهواء. الندى هو مثال على هذا التكثيف. تسمى درجة الحرارة التي يحدث عندها تكثيف عينة من الهواء بنقطة الندى. ويمكن قياسه بسهولة عن طريق تبريد كرة معدنية ببطء؛ نقطة الندى هي درجة الحرارة التي يظهر عندها التكثيف لأول مرة على الكرة.</div>

الضغط الجزئي للغاز هو مقياس للنشاط الديناميكي الحراري لجزيئات الغاز. الضغط الذي سيحدثه الغاز إذا احتل ...

Education

JoVE Core

Physics

الفيزياء

Unit 1

الوحدة الأولى

The Kinetic Theory of Gases

النظرية الحركية للغازات

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

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

equation of state

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molecular kinetic energy

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distribution of molecular speeds

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maxwell-boltzmann-distribution-problem-solving

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The Maxwell-Boltzmann distribution describes how molecular speeds are spread in a gas. Even though individual molecules move in random directions, the whole gas has a predictable speed pattern. This distribution is written as f(v), where v is molecular speed. The distribution function is used to find the expected number of particles with speeds between v1 and v2. Because N is dimensionless, f(v) has units of seconds per meter. The relationship can also be written in differential form for speed...

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Gas collisions: path length and time

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dalton's law of partial pressure

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...

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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 Physics introduces the theory and application of fundamental physics topics, including kinematics, dynamics, fluid mechanics, statics, waves, and acoustics, with concise and easy-to-understand animated videos. Additionally, the scientist-in-action videos demonstrate the application of related concepts in classical and original research experiments performed in today's laboratories worldwide.

Gas Mixtures and Their Partial Pressures

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