What is the formula for finding pressure?

Answer 1

I suppose you mean the formula for the variation in pressure. The simplest expression of this is, at a fixed temperature,and for a given mass of gas, pressure x volume = constant. This is known as Boyle's Law.

If the temperature is changing, then we get two relations:

1. If the pressure is fixed, volume = constant x temperature (absolute)

2. If the volume is fixed, pressure = constant x temperature (absolute)

These can be combined into the ideal gas equation Pressure x Volume = constant x Temperature (absolute), or PV = RT where R = the molar gas constant. (Absolute temperature means degrees kelvin, where zero is -273 celsius)