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Ch 20: The Micro/Macro Connection
Chapter 20, Problem 20

2.0 mol of monatomic gas A initially has 5000 J of thermal energy. It interacts with 3.0 mol of monatomic gas B, which initially has 8000 J of thermal energy. a. Which gas has the higher initial temperature?

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Thermal Energy

Thermal energy refers to the total kinetic energy of the particles in a substance due to their motion. In the context of gases, it is directly related to the temperature and the number of moles of the gas. The more thermal energy a gas has, the higher its temperature, assuming the gas is ideal and behaves according to the ideal gas law.
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Temperature and Moles Relationship

The temperature of a gas is influenced by both its thermal energy and the number of moles present. For monatomic ideal gases, the average kinetic energy per particle is proportional to the temperature. Therefore, to compare the temperatures of two gases, one must consider both their thermal energies and the number of moles, as temperature can be calculated using the formula: T = (2/3)(E/Nk), where E is thermal energy, N is the number of particles, and k is the Boltzmann constant.
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Ideal Gas Law

The Ideal Gas Law (PV = nRT) relates the pressure (P), volume (V), number of moles (n), and temperature (T) of an ideal gas. While this question does not directly involve pressure or volume, understanding this law is crucial for comprehending how gases behave under different conditions. It helps in deriving relationships between thermal energy, temperature, and the number of moles, which are essential for determining which gas has a higher initial temperature.
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