Calculate how nitrogen pressure changes with temperature in a sealed system from a gauge or absolute reading, or solve P, V, n or T with PV = nRT.

Fixed amount of nitrogen in a sealed system with Z unchanged. A pressure difference alone does not prove a leak.

Gauge readings assume sea-level atmosphere, 101.325 kPa (14.696 psi). The answer uses the same basis.

Volume change

Use the same unit for both volumes. 1 and 1 mean the volume does not change.

Related Calculators

Nitrogen Pressure Formula

The following ideal-gas formula calculates absolute nitrogen pressure when Z = 1. The more general relation is P = ZnRT/V with a prescribed compressibility factor appropriate to the solved state. A guessed fixed Z does not replace a validated nitrogen equation of state at high density or near phase boundaries.

P = (n ร— R ร— T) / V

Variables:

  • P is absolute nitrogen pressure in pascals (Pa), not gauge pressure; absolute pressure equals gauge pressure plus local atmospheric pressure
  • n is the number of moles of nitrogen gas
  • R is the molar gas constant, 8.31446261815324 J/(molยทK), equivalent to Paยทmยณ/(molยทK)
  • T is absolute temperature in kelvin, greater than 0 K
  • V is the volume of the container in cubic meters

For the ideal model, multiply the independently known nitrogen amount by R and absolute temperature, then divide by vessel volume in cubic meters. For the prescribed-Z model, also multiply by a state-appropriate Z. The calculator does not determine Z, phase stability, allowable pressure or a safe fill level.

What is a Nitrogen Pressure?

Nitrogen pressure is the normal force per unit area exerted by the gas. Nitrogen is relatively unreactive under many ordinary conditions, but this does not make a pressurized system safe. Nitrogen can displace oxygen and cause asphyxiation, and compressed gas stores hazardous energy. Use equipment ratings, gas-supplier guidance and an approved procedure for the actual application; this gas-law estimate does not approve cylinder filling or pressure testing.

How to Calculate Nitrogen Pressure?

The following steps outline how to calculate the Nitrogen Pressure:

  1. First, determine gas or vessel volume V and convert it to cubic meters for the SI formula; 1 liter = 0.001 mยณ.
  2. Next, determine the temperature of the nitrogen gas (T) in kelvin.
  3. Next, obtain nitrogen amount n independently, for example from a known amount or nitrogen mass and an appropriate molar mass. Do not use an unknown pressure to infer n and then claim to solve that same pressure.
  4. Finally, calculate absolute pressure P = nRT/V for Z = 1, or P = ZnRT/V with a validated state-appropriate Z, using coherent SI units.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Volume of nitrogen gas (V) = 5 liters

Temperature of nitrogen gas (T) = 300 kelvin

Number of moles of nitrogen gas (n) = 2 moles

For the ideal-gas assumption Z = 1, V = 5 L = 0.005 mยณ, n = 2 mol and T = 300 K give P = 2 ร— 8.31446261815324 ร— 300 / 0.005 โ‰ˆ 997,735.514 Pa โ‰ˆ 997.735514 kPa absolute.