What is Pressure?
How hard a gas pushes on its surroundings. Laplaxian works with absolute pressure, in pascal (Pa).
At higher pressure more molecules fit into the same volume, so reactions speed up and equilibrium compositions shift.
Atmospheric pressure at sea level is about 1 atm (101,325 Pa). Air inside a car tyre is at roughly three times that, in absolute terms.
Enter Pa, kPa, bar, atm or MPa. Always enter absolute pressure, not gauge pressure (the difference from atmospheric).
1\,\mathrm{atm} = 101\,325\,\mathrm{Pa}, \qquad 1\,\mathrm{bar} = 10^{5}\,\mathrm{Pa}
From gauge pressure:
P_{\mathrm{abs}} = P_{\mathrm{gauge}} + P_{\mathrm{atm}}
Many pressure gauges read gauge pressure. Entering that value directly would understate the pressure by about 1 atm.