Relation between temperature and average translational kinetic energy.

In summary, there is a misconception that the temperature of a gas is solely related to the average translational kinetic energy of its molecules. However, this is only true for an ideal mono-atomic gas. In reality, molecules can have other modes of motion such as rotational and vibrational, which also contribute to the temperature. Neglecting this restriction can lead to misunderstandings. Thank you to Dale for clarifying this issue.
  • #1
Nikhil Rajagopalan
72
5
Dear Experts,
I have read from various sources that the temperature of a gas is related to the "average translational kinetic energy" of a molecule of gas. When there are molecules that support motion other than translational ,which may also have rotational and vibrational motion, How does those two modes of motion not contribute to the temperature.
 
  • Like
Likes Dale
Science news on Phys.org
  • #2
Nikhil Rajagopalan said:
When there are molecules that support motion other than translational ,which may also have rotational and vibrational motion, How does those two modes of motion not contribute to the temperature.
They do contribute to the temperature. That is in fact why the statement you first made is actually incorrect. It should be “the temperature of an ideal mono-atomic gas is related to the ‘average translational kinetic energy’ of a molecule of gas”.

Unfortunately, that important restriction is often neglected, which leads students to the mistaken conclusion that this relationship to KE is a general relationship instead of one particular to a specific kind of material. You have done well to identify the problem with that description.
 
  • Like
  • Informative
Likes sophiecentaur and Nikhil Rajagopalan
  • #3
Thank you Dale. That was very helpful.
 
  • Like
Likes Dale

1. What is the relationship between temperature and average translational kinetic energy?

The relationship between temperature and average translational kinetic energy is direct and proportional. As temperature increases, the average translational kinetic energy of particles also increases. This means that at higher temperatures, particles have more energy and move faster.

2. How does temperature affect the average translational kinetic energy of particles?

Temperature affects the average translational kinetic energy of particles by increasing or decreasing the speed at which they move. As temperature increases, particles have more energy and move faster, resulting in a higher average translational kinetic energy. On the other hand, as temperature decreases, particles have less energy and move slower, resulting in a lower average translational kinetic energy.

3. What is the formula for calculating average translational kinetic energy?

The formula for calculating average translational kinetic energy is KE = 1/2 * m * v^2, where KE is the kinetic energy, m is the mass of the particle, and v is the velocity of the particle.

4. How does the mass of particles affect the average translational kinetic energy at a given temperature?

The mass of particles does not directly affect the average translational kinetic energy at a given temperature. However, it does affect the velocity of the particles, which in turn affects the average translational kinetic energy. Lighter particles will have a higher velocity and therefore a higher average translational kinetic energy compared to heavier particles at the same temperature.

5. What is the significance of understanding the relationship between temperature and average translational kinetic energy?

Understanding the relationship between temperature and average translational kinetic energy is crucial in many scientific fields, such as thermodynamics and chemistry. It helps us understand the behavior and properties of particles at different temperatures and how they affect their surroundings. This knowledge is also essential in various industrial and technological applications, such as in the design of engines and refrigeration systems.

Similar threads

Replies
6
Views
1K
Replies
16
Views
1K
Replies
23
Views
1K
Replies
10
Views
1K
Replies
5
Views
2K
Replies
4
Views
1K
Replies
32
Views
2K
  • Thermodynamics
Replies
4
Views
2K
Replies
2
Views
473
Replies
1
Views
1K
Back
Top