💏intro to chemistry review

key term - First law of thermodynamics

Definition

The first law of thermodynamics states that energy cannot be created or destroyed, only transferred or converted from one form to another. In chemistry, it is often formulated as $\Delta U = Q - W$, where $\Delta U$ is the change in internal energy, $Q$ is the heat added to the system, and $W$ is the work done by the system.

5 Must Know Facts For Your Next Test

  1. The first law of thermodynamics is also known as the law of energy conservation.
  2. In a closed system, any increase in internal energy must come from heat added to the system or work done on the system.
  3. For an ideal gas undergoing an isothermal process, $\Delta U = 0$ and thus $Q = W$.
  4. If a process occurs at constant volume (isochoric), no work is done ($W=0$), so $\Delta U = Q_v$, where $Q_v$ is heat at constant volume.
  5. For a cyclic process, where the system returns to its initial state, the net change in internal energy over one cycle ($\Delta U_{cycle}$) is zero.

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