Name: gas pressure patterns in kinetic molecular theory
Uploaded: 2020-09-03T13:38:27.000Z
Duration: 2 min 34 s
Channel: JoVE

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PS.Chm.7.3

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Kinetic Molecular Theory and Gas Laws Explain Properties of Gas Molecules

Наблюдения за различными свойствами газа, выраженными в различных газовых законах, выведенных Бойлем, Шарлем, Гей-Люссаком и Авогадро, следуют из кинетической молекулярной теории, являющейся их основой. Давление, оказываемое газом, возникает в результате ударов постоянно движущихся частиц о стенки емкости. Уменьшение объема емкости, при сохранении постоянного числа молей и температуры, сближает частицы газа, уменьшая расстояние между ними.В этом меньшем объеме увеличивается плотность газа и частота столкновений частота столкновений молекул со стенками. Следовательно, давление, оказываемое газом, увеличивается. Обратное соотношение между давлением и объемом определяется законом Бойля.Добавление большего количества молей газа в емкость при постоянной температуре увеличивает плотность газа и, следовательно, частоту столкновений. Чтобы поддерживать начальное давление, объем должен увеличиваться. Эта прямая зависимость между объемом и молями, задается законом Авогадро.Теперь представьте, что количество молей остается постоянным, а температура повышается. Поскольку средняя кинетическая энергия частиц газа увеличивается пропорционально температуре, частицы сталкиваются чаще и сильнее. Если объем поддерживается постоянным при увеличении температуры, плотность газа и частота столкновений увеличиваются, и, следовательно, давление также увеличивается.Прямая связь между давлением и температурой определяется законом Гей-Люссака. Если, с другой стороны, давление должно оставаться постоянным вместе с постоянным числом молей, тогда повышение температуры должно сопровождаться увеличением объема, чтобы распределить столкновения по большей площади поверхности. Эта прямая зависимость между объемом и температурой изложена в законе Чарльза.Наконец, согласно кинетической молекулярной теории, частицы газа не притягиваются и не отталкиваются друг от друга. В смеси разных газов компоненты действуют независимо, и на их индивидуальное давление не влияет присутствие другого газа. Таким образом, полное давление смеси является суммой отдельных парциальных давлений.Это закон Дальтона.

Молекулярно-кинетическая теория и газовые законы

Доказательство молекулярно-кинетической теории (KMT) и ее постулатов – это ее способность объяснить и описать поведение газа. Различные газовые законы (законы Бойля, Чарльза, Гей-Люссака, Авогадро и Дальтона) могут быть основаны на предположениях КМТ, которые привели к тому, что химики считают, что предположения теории точно отражают свойства молекул газа. 
 
 <h4>Молекулярно-кинетическая теория объясняет поведение газов </h4>
 
 Напоминая о том, что давление газа воздействует на быстро движущиеся молекулы газа и напрямую зависит от количества молекул, которые ударяются по единице стенки за единицу времени, KMT концептуально объясняет поведение газа следующим образом: 
 
 <ul>
 <li>Закон Гея-Люссака: Если температура повышается, то средняя скорость и кинетическая энергия молекул газа увеличиваются. Если объем удерживается постоянным, то увеличение скорости молекул газа приводит к более частым и более сильным столкновениям со стенками контейнера, тем самым увеличивая давление. Это также называется законом Амонтона. </li>
 <li>Закон Чарльза: Если температура газа повышается, то постоянное давление может поддерживаться только в том случае, если объем газа увеличивается. Это приведет к увеличению среднего расстояния, пройденного молекулами для достижения стенок контейнера, а также к увеличению площади поверхности стены. Эти условия снижают как частоту столкновений молекул со стенками, так и количество столкновений на единицу площади, и объединенные эффекты уравновешивает влияние возросших сил столкновения из-за большей кинетической энергии при более высокой температуре. </li>
 <li>Закон Бойля: Если объем газа уменьшается, площадь стенки контейнера уменьшается, а частота столкновений молекулы-стены увеличивается, и оба эффекта увеличивают давление газа. </li>
 <li>Закон Авогадро: При постоянном давлении и температуре частота и сила столкновений молекул и стенок постоянны. В таких условиях увеличение количества молекул газа потребует пропорционального увеличения объема контейнера, чтобы уменьшить количество столкновений на единицу площади для компенсации повышенной частоты столкновений. </li>
 <li>Закон Дальтона: Из-за больших расстояний между ними, молекулы одного газа в смеси бомбардируют стенки контейнера с такой же частотой, независимо, присутствуют ли другие газы или нет, а общее давление газовой смеси равняется сумме (частичных) давлений отдельных газов. </li>
 </ul>
 
 Этот текст адаптирован из <a href=""https://openstax.org/books/chemistry-2e/pages/9-5-the-kinetic-molecular-theory"">Openstax, Химия 2е изд., раздел 9.5: Молекулярно-кинетическая теория.</a>"

Проверкой кинетической молекулярной теории (КМТ) и ее постулатов является ее способность объяснять и описывать поведение газа. Различные законы о газе ...

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KEY TERMS AND CONCEPTS

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gas pressure patterns in kinetic molecular theory

Kinetic molecular theory explains gas pressure by linking it to the motion of gas molecules. Gas pressure comes from rapidly moving molecules hitting the walls of a container. It depends on how many molecules strike a unit area in a given time.

The theory also helps explain the main gas laws. In Gay-Lussac’s law, also called Amontons’s law, raising temperature increases the average speed and kinetic energy of gas molecules. If volume stays constant, the molecules collide with the walls more often and more forcefully, so pressure increases.

Charles’s law shows what happens when temperature rises at constant pressure. The gas must expand to keep pressure steady. That larger volume means molecules travel farther before reaching the walls, and the wall area increases too. These changes lower collision frequency and the number of collisions per unit area, which balances the stronger collisions caused by the higher kinetic energy.

Boyle’s law describes the effect of smaller volume. When gas volume decreases, the container wall area also decreases. Molecule-wall collisions become more frequent, and the pressure rises. Avogadro’s law says that at constant pressure and temperature, the collision rate and collision force stay constant. If the number of gas molecules increases, the volume must increase in proportion so the collisions per unit area can drop enough to offset the added molecules.

Dalton’s law applies to gas mixtures. Because gas molecules are far apart, one gas in a mixture strikes the container walls with the same frequency whether other gases are present or not. The total pressure of the mixture equals the sum of the partial pressures of the individual gases. These gas laws show how the assumptions of kinetic molecular theory fit the behavior of gases.

Gas Pressure Patterns in Kinetic Molecular Theory

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kinetic molecular theory and gas laws explain properties of gas molecules

Kinetic molecular theory explains gas pressure by linking it to the motion of gas molecules. Gas pressure comes from rapidly moving molecules hitting the walls of a container. It depends on how many molecules strike a unit area in a given time. The theory also helps explain the main gas laws. In Gay-Lussac’s law, also called Amontons’s law, raising temperature increases the average speed and kinetic energy of gas molecules. If volume stays constant, the molecules collide with the walls more...

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Explore how kinetic molecular theory explains gas pressure, temperature, volume changes, and the gas laws of Boyle, Charles, Gay-Lussac, Avogadro, and Dalton.

Gas Pressure Patterns in Kinetic Molecular Theory | JoVE K12

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Gas Pressure Patterns in Kinetic Molecular Theory

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