Thermodynamics Conceptual Question

AI Thread Summary
The discussion revolves around a thermodynamics question regarding the relationship between added energy, internal energy, and temperature. The original poster is confused about how adding energy can increase temperature without affecting kinetic or potential energy, leading to a clarification about the definitions of kinetic and potential energy at the macroscale. It is confirmed that adding energy does indeed increase internal energy, which in turn raises temperature. The connection between volume and temperature is also acknowledged, reinforcing that an increase in volume can contribute to temperature rise. Overall, the poster's understanding is validated, emphasizing the correct interpretation of thermodynamic principles.
fridakahlo
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Hi! I'm new to the forums, so I apologize in advance if I'm posting my question in the wrong section. I'm studying thermodynamics right now, and I came across this sentence from my book:

Homework Statement


"When energy is added to a system and there is no change in the kinetic or potential energy of the system, the temperature of the system usually rises."

Homework Equations


Volume is proportional to Temperature
Internal Energy= Bond energy + Thermal energy

The Attempt at a Solution


I'm confused. Wouldn't adding energy to the system increase the system's internal energy (therefore inc. its kinetic/potential energy)? The only way I can see the above statement to be true is if there was an increase in volume of the system. And since volume is proportional to temperature, the temperature of the system would also rise. Are my assumptions correct or am I overthinking it? :oldconfused:
 
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fridakahlo said:
Hi! I'm new to the forums, so I apologize in advance if I'm posting my question in the wrong section. I'm studying thermodynamics right now, and I came across this sentence from my book:

Homework Statement


"When energy is added to a system and there is no change in the kinetic or potential energy of the system, the temperature of the system usually rises."

Homework Equations


Volume is proportional to Temperature
Internal Energy= Bond energy + Thermal energy

The Attempt at a Solution


I'm confused. Wouldn't adding energy to the system increase the system's internal energy (therefore inc. its kinetic/potential energy)? The only way I can see the above statement to be true is if there was an increase in volume of the system. And since volume is proportional to temperature, the temperature of the system would also rise. Are my assumptions correct or am I overthinking it? :oldconfused:
In this context, when they are talking about kinetic or potential energy, they are referring to the macroscale. The potential energy they are referring to is gravitational potential energy, and the kinetic energy they are referring to is based on the mass average velocity over each small localized volume including a huge number of molecules.

Your interpretation that the internal energy increases and the temperature increases is totally correct.
 
Thanks Chestermiller!
 
Last edited:

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