Internal Energy Change Calculator

Calculate Changes in Thermodynamic Energy

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First Law Calculator

Calculate internal energy change using heat and work.

Internal Energy Change: - J

Ideal Gas Internal Energy Calculator

Calculate internal energy change for an ideal gas using temperature change.

Internal Energy Change: - J

Phase Change Energy Calculator

Calculate internal energy change during phase transitions.

Internal Energy Change: - J

Understanding Internal Energy

What is Internal Energy?

Internal energy (U) is the total energy contained within a system, including:

  • Kinetic energy of molecules
  • Potential energy of molecular interactions
  • Chemical bond energy
  • Nuclear energy

First Law of Thermodynamics

The First Law relates internal energy change to heat and work:

  • ΔU = Q - W (work done by system)
  • ΔU = Q + W (work done on system)
  • Energy is conserved
  • Path-independent property

Ideal Gas Internal Energy

For ideal gases:

  • ΔU depends only on temperature change
  • ΔU = nCvΔT
  • Independent of volume changes
  • Independent of pressure changes

Phase Changes

During phase transitions:

  • Temperature remains constant
  • Energy changes internal structure
  • Latent heat represents energy change
  • Different for fusion and vaporization

Essential Internal Energy Formulas

First Law

ΔU = Q - W

Where Q is heat added and W is work done by system

Ideal Gas

ΔU = nCvΔT

Where n is moles, Cv is heat capacity, ΔT is temperature change

Phase Change

ΔU = mL

Where m is mass and L is latent heat