Behavior of Air Molecules when Heated

In summary, as the gas in the sealed container is heated, the average distance between the gas molecules remains unchanged when the container has a fixed volume, but increases when the container is allowed to expand. The frequency of the molecules' collision with the walls increases as the molecules move faster, but it is uncertain how much it will change when the container is allowed to expand, as it depends on the temperature increase and the amount of expansion.
  • #1
Betadine
15
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Homework Statement

Some gas is heated in a sealed container. How do the average distance between the gas molecules, and the frequency of the molecules' collision with the walls, change when the container

(A) has a fixed volume, and
(B) is allowed to expand outwards?



The attempt at a solution

(A) Container has a fixed volume
1) I am not sure about the average distance. The molecules move faster, but they are kept in a fixed space. Does that mean that the average distance remains unchanged?
2) The frequency of the molecules' collision with the walls will increase, since the molecules are moving faster.

(B) Container is allowed to expand
1) Will the average distance increase since there is more space for them to move?
2) The frequency of the molecules' collision will remain unchanged?



Will appreciate any guidance. Thank you!
 
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  • #2
Betadine™ said:
Homework Statement

Some gas is heated in a sealed container. How do the average distance between the gas molecules, and the frequency of the molecules' collision with the walls, change when the container

(A) has a fixed volume, and
(B) is allowed to expand outwards?



The attempt at a solution

(A) Container has a fixed volume
1) I am not sure about the average distance. The molecules move faster, but they are kept in a fixed space. Does that mean that the average distance remains unchanged?
2) The frequency of the molecules' collision with the walls will increase, since the molecules are moving faster.
1) I agree with your thinking.
2) I agree with your thinking. Hotter molecules move faster.

(B) Container is allowed to expand
1) Will the average distance increase since there is more space for them to move?
2) The frequency of the molecules' collision will remain unchanged?
1) I agree with your thinking.
2) We aren't told how much the container is allowed to expand. Suppose just 1% expansion. If we increase the temp by a large amount then collision frequency will be more. So I think we can't say anything definite about the collision frequency, other than it can be expected to change.
 
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1. What happens to air molecules when they are heated?

When air molecules are heated, they gain kinetic energy and begin to move faster. This causes the molecules to spread out and become less dense. As a result, the air expands and takes up more space.

2. Why does hot air rise?

Hot air rises because it is less dense than cold air. As the air molecules gain kinetic energy and spread out, they take up more space and become lighter. This lighter air then rises, while the denser, cooler air sinks.

3. How does the behavior of air molecules change with temperature?

The behavior of air molecules is directly related to temperature. As the temperature increases, the molecules gain more kinetic energy and move faster, causing the air to expand and become less dense. On the other hand, as the temperature decreases, the molecules slow down and the air becomes more dense.

4. What is the relationship between air pressure and temperature?

As the temperature of air increases, the air molecules gain more kinetic energy and spread out, causing the air to expand and take up more space. This decrease in density leads to a decrease in air pressure. Conversely, as the temperature decreases, the air becomes more dense and the air pressure increases.

5. How does heating air affect weather patterns?

Heating air can have a significant impact on weather patterns. As hot air rises, it can create areas of low pressure, which can lead to the formation of storms and other weather phenomena. Additionally, the movement of air due to heating can also influence wind patterns and air currents, which play a major role in the overall weather patterns of a region.

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