Name: isothermal expansion and heat transfer
Uploaded: 2025-08-19T15:10:28.000Z
Duration: 1 min 21 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Chemistry

Energy

HS-PS3-4

Isothermal Processes

Sabit bir sıcaklıkta meydana gelen termodinamik bir sürece izotermal süreç denir.
Kaynar suyun 100 santigrat derece sabit bir sıcaklıkta buhara dönüştürülmesi, izotermal bir işleme bir örnektir. Benzer şekilde, suyun 0 santigrat derecede buza dönüştürülmesi de izotermal bir süreçtir.
Sıcaklık değişmediği için bu işlemler için iç enerjideki değişim sıfırdır. Böylece, termodinamiğin birinci yasasını kullanarak, yapılan iş ısıya eşittir.
Şimdi, sabit bir sıcaklıkta kapalı bir gaz şırıngası içine yerleştirilmiş ideal bir gaz sistemi düşünün.
Piston kontrollü bir şekilde yavaşça itildiğinde, şırınganın içindeki gaz sıkıştırılır. Gazın azalan hacmi basınçta bir artışa neden olur, ancak sıcaklık sabit kalır.
Pistonun kontrollü bir şekilde serbest bırakılması, gazın sabit sıcaklıkta genleşmesine yol açar.
Herhangi bir izotermal süreç için pV eğrisi hiperboliktir, çünkü basınç, sabit bir sıcaklıkta ideal bir gaz için hacimle ters orantılıdır.

<ol>
	<li>Genç, H. D ve Freedman, R.A. (2012). Modern Fizik ile Üniversite Fiziği. San Francisco, Kaliforniya: Pearson. sayfa 635.</li>
	<li>Stax'ı açın. (2019). Üniversite Fiziği Cilt 2. [Web sürümü]. pp 121 <a href="https://openstax.org/books/college-physics/pages/15-2-the-first-law-of-thermodynamics-and-some-simple-processes" adresinden alındı>https://openstax.org/books/college-physics/pages/15-2-the-first-law-of-thermodynamics-and-some-simple-processes</a></li>
</ol>

İzotermal işlemler

Sabit sıcaklıkta gerçekleşen bir termodinamik işleme izotermal işlem denir. Isı, termal dengeyi korumak için sistemden yavaş yavaş akar veya sistemden dışarı akar. Su buharı haline buğulama veya dondurma gibi faz değişikliklerini içeren işlemler, sabit sıcaklıkta izotermal işlemlere örnek olarak verilebilir.

Bir ideal gaz da izotermal genleşme veya sıkışma geçirebilir.

Örneğin, izole bir silindir içindeki 1 mol ideal gazı düşünelim. İlk hacim V ve basınç p olsun. Sisteme eklenen ısı, gazın sabit bir sıcaklık olan 300 K'daki kısmi bir genişlemesine sebep olursa, gazın hacmi 2V'ye değişirse, sisteme eklenen ısı miktarı nedir?

Burada bilinen miktarlar gazın mol sayısı, başlangıç ve son hacmidir. Bilinmeyen miktar ise ısıdır ve hesaplanmalıdır.

Termodinamiğin birinci yasası göre,

<img alt="Equation1" src="/files/ftp_upload/13682/13682_Equation_PT_1.svg" style="text-align: center; height: 13px;" />

Q = Î&#148;U + W

Sıcaklık sabit olduğu için bu işlem için iç enerjinin değişimi sıfırdır. Bu nedenle, sisteme eklenen ısı, sistem tarafından yapılan işe eşittir.

<img alt="Equation2" src="/files/ftp_upload/13682/13682_Equation_PT_2.svg" style="text-align: center; height: 13px;" />

şimdi, ideal bir gazın izotermal genişleme sırasında yaptığı iş şu şekildedir:

<img alt="Equation3" src="/files/ftp_upload/13682/13682_Equation_PT_3.svg" style="text-align: center; height: 32px;" />

W = nRT ln(Vf/Vi)

Bunu gazın mol sayısı, gaz sabiti, sıcaklık, başlangıç hacmi ve gazın son hacmi yerine koyarak, yapılan iş 1728.85 J'ye eşittir.

Sistem tarafından yapılan iş, sisteme eklenen ısının eşit olduğu düşünüldüğünde, sisteme 2V'ye izotermal olarak genişlemesi için 1728.85 J ısı uygulandığı kabul edilir.

Sabit sıcaklıkta meydana gelen termodinamik bir sürece izotermal süreç denir. Isı yavaşça sisteme veya sistemden dışarı akar ...

Education

JoVE Core

Physics

Fizik

Unit 1

Ünite 1

The First Law of Thermodynamics

Termodinamiğin Birinci Kanunu

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

isothermal expansion and heat transfer

An isothermal process is a thermodynamic process that happens at constant temperature. During the process, heat slowly flows into the system or out of the system so thermal equilibrium is maintained.

Phase changes are common examples of isothermal processes. Water can evaporate into steam at a constant temperature, and water can also freeze into ice at a constant temperature. An ideal gas can also undergo isothermal expansion or compression.

Here, an ideal gas in an isolated cylinder expands quasistatically at 300 K. The gas starts with 1 mole at volume V and pressure p. The volume then changes to 2V, and the heat added to the system must be found.

By the first law of thermodynamics, the change in internal energy is zero because the temperature stays constant. That means the heat added to the system equals the work done by the system. For an ideal gas in isothermal expansion, the work is calculated from the initial and final volume.

Substituting the number of moles, gas constant, temperature, and volumes gives a work value of 1728.85 J. Since the work done by the gas equals the heat added, 1728.85 J of heat is applied to expand the gas isothermally to 2V.

Isothermal Expansion and Heat Transfer

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isothermal processes

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key terms and concepts

Learn how isothermal processes keep temperature constant while heat equals work during ideal gas expansion, with phase change and cylinder examples.

Isothermal Expansion and Heat Transfer | JoVE K12

physics

JoVE Temel Fizik, kinematik, dinamik, akışkanlar mekaniği, statik, dalgalar ve akustik dahil olmak üzere temel fizik konularının teorisini ve uygulamasını kısa ve anlaşılması kolay animasyonlu videolarla tanıtıyor. Ek olarak, sektör içindeki bilim insanı videoları, dünya çapındaki günümüz laboratuvarlarında gerçekleştirilen klasik ve orijinal araştırma deneylerinde ilgili kavramların uygulanmasını göstermektedir.

new-jersey-student-learning-standards-for-science

New Jersey Student Learning Standards for Science

Physical Science

HS-PS3-1

Florida Department of Education

SC.912.P.10

SC.912.P.10.2

new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Energy

HS-PS3-3.

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HS-PS3-6

Isothermal Expansion and Heat Transfer

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