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# Thermodynamics ## 1st Law of Thermodynamics $\Delta U = Q - W$ * $\Delta U$ = change in internal energy * $Q$ = heat added to the system * $W$ = work done by the system ### Types of Processes * **Adiabatic**: $Q = 0$, $\Delta U = -W$ * **Constant Volume**: $W = 0$, $\Delta U = Q$ *...

# Thermodynamics ## 1st Law of Thermodynamics $\Delta U = Q - W$ * $\Delta U$ = change in internal energy * $Q$ = heat added to the system * $W$ = work done by the system ### Types of Processes * **Adiabatic**: $Q = 0$, $\Delta U = -W$ * **Constant Volume**: $W = 0$, $\Delta U = Q$ * **Isothermal**: $\Delta U = 0$, $Q = W$ * **Cyclical**: $\Delta U = 0$, $Q = W$ ### Heat $Q = mc\Delta T$ * $m$ = mass * $c$ = specific heat * $\Delta T$ = change in temperature Also, $Q = mL$ * $L$ = latent heat ## 2nd Law of Thermodynamics ### Entropy $\Delta S = \frac{Q}{T}$ * $\Delta S$ = change in entropy * $T$ = temperature (in Kelvin) ### Efficiency $e = 1 - \frac{T_{c}}{T_{H}}$ * $T_{c}$ = temperature of the cold reservoir * $T_{H}$ = temperature of the hot reservoir Also, $e = \frac{W}{Q_{H}}$ $W = Q_{H} - Q_{c}$ ### Heat Engine A diagram of a heat engine is shown. It takes heat $Q_{H}$ from a hot reservoir, performs work $W$, and exhausts heat $Q_{c}$ into a cold reservoir.