Which molecules will move faster?

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Discussion Overview

The discussion revolves around the movement of gas molecules in two balloons filled with helium at different volumes (5 liters and 10 liters). Participants explore concepts from the Kinetic Molecular Theory (KMT) and the combined gas law, particularly focusing on the implications of volume and temperature on molecular speed.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant suggests that the molecules in both balloons would move at the same speed, based on the KMT, which states that the kinetic energy of gas particles depends only on temperature.
  • Another participant introduces Gay-Lussac's law, arguing that since volume is directly proportional to temperature, the larger volume (10 L) should result in higher temperature and thus faster-moving molecules.
  • A later reply questions the relationship between pressure, volume, and temperature by referencing the ideal gas law equations (PV = RT and PV = nRT).

Areas of Agreement / Disagreement

Participants express differing views on the relationship between volume, temperature, and molecular speed, indicating that the discussion remains unresolved with competing interpretations of the KMT and gas laws.

Contextual Notes

The discussion assumes constant temperature but does not clarify the implications of volume changes on temperature within the context of the problem.

holydog23
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In class today, we were talking about the Kinetic Molecular Theory and the combined gas law. I was understanding everything until our teacher threw in a question that confused me really bad

Suppose we fill two balloons with Helium gas. One of them is filled 5 liters of He and the other to 10 Liters. The molecules of which balloon will move faster?

He didn't mention anything about the temperature, so I'm assuming constant temperature here because inflating balloons doesn't change temperature. Nevertheless, this question has my head spinning; a detailed explanation would be appreciated
 
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What's your head tell you?
 
Bystander said:
What's your head tell you?
Well I postulated that the molecules in both balloons would move at the same speed; this is because according to the KMT, Kinetic Energy of gas particles is dependent only on temperature, so they should be at the same speed. But because of Gay-lussac's law, Volume is directly proportional to temperature, so if the volume increases, the temperature should increase and thus make the molecules within the 10 L faster. But this contradicts the KMT since it states that KE of these molecules is dependent ONLY on temperature
 
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PV = RT, or PV = nRT?
 

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