The Ideal Gas Law

One equation, PV = nRT, ties pressure, volume, temperature and amount of gas together. Drag a slider and watch the molecules respond — hotter gas moves faster, a smaller volume packs more collisions, and the pressure readout tracks it all. The preset buttons freeze one quantity so Boyle's, Charles's and Gay-Lussac's laws fall out on their own.

Pressure  P = nRT ÷ V
100.00 kPa
0.987 atm
Molecules  N = n·NA
6.02 × 1023
at n = 1.00 mol
Molar volume  Vm = V ÷ n
22.71 L/mol
rms speed 493 m/s
Amount 1.00 mol
Temperature 273.15 K
Volume 22.711 L
Gas: nitrogen (N2) · molar mass M = 0.02802 kg/mol · R = 8.314 J/(mol·K)
Tip: press Charles, then raise the temperature — the piston lifts so the pressure stays put. That is V ∝ T at constant P.