[[Thermodynamics]]
# Summary
* First law: $\Delta U=Q+W$
* Q is heat added W is work done
* Internal energy $U$ is the sum of kinetic energy and potential energy. Ideal gas has no internal potential energy, so solely kinetic.
* Ideal monatomic gas has formula: $U=\frac{3}{2}Nk_BT=\frac{3}{2}nRT$ 
* Work done on gas by external pressure: $W=-P\Delta V$
* Negative sign means expansion does negative work on gas.
* On a PV graph, integrals are work done, and straight lines are isotherms.
* Four special processes:
	* Isovolumeric $W = 0$
	* Isothermic $\Delta U = 0$ For an ideal gas
	* Isobaric $W=-P\Delta V$
	* Adiabatic $Q=0$