The first of the [[Laws of Thermodynamics|laws of the thermodynamics]] states that [[Energy|energy]] can not be created or destroyed, only transformed. The first law for a [[Control Mass|control mass]] is as follows: $Q = \Delta U+\Delta K+\Delta P + W$ For a steady-state control volume system the first law is as follows: $\dot{Q}=\Delta\dot{H}+\Delta\dot{K}+\Delta\dot{P}+\dot{W}$ Where: - $Q$ is [[Heat|heat]] input, energy transfer due to a [[Temperature|temperature]] difference - $W$ is [[Work|work]] output, energy transfer due to a [[Force|force]] acting over a [[Distance|distance]] - $\Delta U$ is [[Internal Energy|internal energy]] change of a [[Substance|substance]] - $\Delta H$ is [[Enthalpy|enthalpy]] change of a substance - $\Delta K$ is [[Kinetic Energy|kinetic energy]] change - $\Delta P$ is [[Gravitational Potential Energy|potential energy]] change