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Internal Energy Equation:
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Internal energy (U) is a fundamental concept in thermodynamics that represents the total energy contained within a system. It includes the kinetic and potential energies of all particles within the system.
The calculator uses the internal energy equation:
Where:
Explanation: This equation represents the first law of thermodynamics, stating that the change in internal energy of a system equals the heat added to the system minus the work done by the system.
Details: Calculating internal energy is essential for understanding energy transfers in thermodynamic systems, analyzing heat engines, refrigeration cycles, and studying various physical and chemical processes.
Tips: Enter heat (Q) and work (W) values in joules. Positive values indicate heat added to the system and work done by the system. Negative values indicate heat removed from the system and work done on the system.
Q1: What is the sign convention for Q and W?
A: Q is positive when heat is added to the system. W is positive when work is done by the system on the surroundings.
Q2: Can internal energy be negative?
A: Yes, internal energy change can be negative if more work is done by the system than heat is added to it.
Q3: What are typical units for internal energy?
A: The SI unit is joules (J), though other energy units like calories or electronvolts may be used in specific contexts.
Q4: Does this equation apply to all systems?
A: This simplified form applies to closed systems where only heat and work transfers occur. More complex systems may require additional terms.
Q5: How is internal energy related to temperature?
A: For ideal gases, internal energy is directly proportional to temperature. For real substances, the relationship is more complex and depends on the specific properties of the material.