AP Chemistry / Unit 3: Properties of Substances and Mixtures
3.4 Ideal Gas Law
Notes
$$PV=nRT$$
- $T$ must be in kelvins. $R=0.08206$ L·atm/(mol·K).
- Dalton's law: total pressure is the sum of partial pressures; $P_A=X_AP_{total}$.
Practice
At constant $n$ and $T$, doubling $V$ makes $P$:
$\displaystyle P\propto\frac{1}{V}$.
25°C in kelvins:
Add 273.
A mixture has 2 mol $\mathrm{N_2}$ and 2 mol $\mathrm{O_2}$ at 4 atm total. $P_{O_2}=$
Mole fraction 0.5.
Ready for more? Take the Unit 3 test.