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drgetwrekt
drgetwrekt
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collisions don't lead to cooling (except if it causes bonding and release of a photon, or increase in molecular vibrational energy), otherwise this would violate energy conservation (if the gas is an isolated system). However, if the gas has intra-molecular potential energy, expansion would lead to cooling because you need energy to compensate for the lower negative potential energy overall. Since on average the total energy is $\sim T - P$, with $T$ the thermal energy and $P$ the potential energy. Upon expansion $P$ becomes less negative, as such $T$ has to decrease to conserve energy.

collisions don't lead to cooling (except if it causes bonding and release of a photon), otherwise this would violate energy conservation (if the gas is an isolated system). However, if the gas has intra-molecular potential energy, expansion would lead to cooling because you need energy to compensate for the lower negative potential energy overall. Since on average the total energy is $\sim T - P$, with $T$ the thermal energy and $P$ the potential energy. Upon expansion $P$ becomes less negative, as such $T$ has to decrease to conserve energy.

collisions don't lead to cooling (except if it causes bonding and release of a photon, or increase in molecular vibrational energy), otherwise this would violate energy conservation (if the gas is an isolated system). However, if the gas has intra-molecular potential energy, expansion would lead to cooling because you need energy to compensate for the lower negative potential energy overall. Since on average the total energy is $\sim T - P$, with $T$ the thermal energy and $P$ the potential energy. Upon expansion $P$ becomes less negative, as such $T$ has to decrease to conserve energy.

added 54 characters in body
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drgetwrekt
drgetwrekt
  • 92
  • 2

collisions don't lead to cooling (except if it causes bonding and release of a photon), otherwise this would violate energy conservation (if the gas is an isolated system). However, if the gas has intra-molecular potential energy, expansion would lead to cooling because you need energy to compensate for the lower negative potential energy overall. Since on average the total energy is $\sim T - P$, with $T$ the thermal energy and $P$ the potential energy. Upon expansion $P$ becomes less negative, as such $T$ has to decrease to conserve energy.

collisions don't lead to cooling, otherwise this would violate energy conservation (if the gas is an isolated system). However, if the gas has intra-molecular potential energy, expansion would lead to cooling because you need energy to compensate for the lower negative potential energy overall. Since on average the total energy is $\sim T - P$, with $T$ the thermal energy and $P$ the potential energy. Upon expansion $P$ becomes less negative, as such $T$ has to decrease to conserve energy.

collisions don't lead to cooling (except if it causes bonding and release of a photon), otherwise this would violate energy conservation (if the gas is an isolated system). However, if the gas has intra-molecular potential energy, expansion would lead to cooling because you need energy to compensate for the lower negative potential energy overall. Since on average the total energy is $\sim T - P$, with $T$ the thermal energy and $P$ the potential energy. Upon expansion $P$ becomes less negative, as such $T$ has to decrease to conserve energy.

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drgetwrekt
drgetwrekt
  • 92
  • 2

collisions don't lead to cooling, otherwise this would violate energy conservation (if the gas is an isolated system). However, if the gas has intra-molecular potential energy, expansion would lead to cooling because you need energy to compensate for the lower negative potential energy overall. Since on average the total energy is $\sim T - P$, with $T$ the thermal energy and $P$ the potential energy. Upon expansion $P$ becomes less negative, as such $T$ has to decrease to conserve energy.