Calculate a gas’s new pressure when its volume changes using Boyle’s law, or find the new volume, with options for a temperature change and moles of gas.
Pressure Formula
For an ideal gas, calculate absolute pressure from moles n, kelvin temperature T and volume V. For a fixed gas amount, the other calculator modes use P₁V₁ = P₂V₂ at constant temperature or P₁V₁/T₁ = P₂V₂/T₂ when temperature changes. These models omit phase changes and real-gas effects.
- Where P is the Pressure (Pa)
- V is the total volume (m3)
- n is the amount of substance (moles)
- T is the temperature (K)
- R is the universal gas constant (8.31446261815324 J/(K·mol))
| Atmospheres (atm) | Kilopascals (kPa) | Bar (bar) | Pounds per square inch (psi) | Pascals (Pa) |
|---|---|---|---|---|
| 0.1 | 10.133 | 0.10133 | 1.47 | 10132.5 |
| 0.2 | 20.265 | 0.20265 | 2.94 | 20265.0 |
| 0.3 | 30.398 | 0.30398 | 4.41 | 30397.5 |
| 0.4 | 40.530 | 0.40530 | 5.88 | 40530.0 |
| 0.5 | 50.663 | 0.50663 | 7.35 | 50662.5 |
| 0.6 | 60.795 | 0.60795 | 8.82 | 60795.0 |
| 0.7 | 70.928 | 0.70928 | 10.29 | 70927.5 |
| 0.8 | 81.060 | 0.81060 | 11.76 | 81060.0 |
| 0.9 | 91.193 | 0.91193 | 13.23 | 91192.5 |
| 1.0 | 101.325 | 1.01325 | 14.70 | 101325.0 |
| 1.1 | 111.458 | 1.11458 | 16.17 | 111457.5 |
| 1.2 | 121.590 | 1.21590 | 17.64 | 121590.0 |
| 1.3 | 131.723 | 1.31723 | 19.10 | 131722.5 |
| 1.4 | 141.855 | 1.41855 | 20.57 | 141855.0 |
| 1.5 | 151.988 | 1.51988 | 22.04 | 151987.5 |
| 1.6 | 162.120 | 1.62120 | 23.51 | 162120.0 |
| 1.7 | 172.253 | 1.72253 | 24.98 | 172252.5 |
| 1.8 | 182.385 | 1.82385 | 26.45 | 182385.0 |
| 1.9 | 192.518 | 1.92518 | 27.92 | 192517.5 |
| 2.0 | 202.650 | 2.02650 | 29.39 | 202650.0 |
| Exact factors used: 1 atm = 101325 Pa = 101.325 kPa = 1.01325 bar ≈ 14.6959 psi. | ||||
How to Calculate Pressure?
The following example problems outline how to calculate the Pressure.
Example Problem #1
- First, determine the total volume (m3). In this example, the total volume (m3) is given as 50.
- Next, determine the amount of substance (moles). For this problem, the amount of substance (moles) is given as 10.
- Next, determine the temperature (K). In this case, the temperature (K) is found to be 50.
- Finally, calculate the Pressure using the formula above:
P = nRT / V
Inserting the values from above and solving yields:
P = 10 × 8.31446261815324 × 50 / 50 ≈ 83.14462618 Pa
Example Problem #2
Using the same method as above, determine the variables required by the equation. For this example problem, these are provided as:
total volume (m3) = 501
amount of substance (moles) = 59
temperature (K) = 19
Entering these given values yields:
P = 59 × 8.31446261815324 × 19 / 501 ≈ 18.60381755 Pa
