Universal Gas Constant R Unit Converter

How to Calculate Universal Gas Constant R Between Units

The Universal Gas Constant R Unit Converter converts the numerical value of the gas constant R between various units used in thermodynamics and ideal gas law (PV = nRT). The conversion formula is:

\( R_{output} = R_{input} \times \frac{R_{value\ in\ output\ unit}}{R_{value\ in\ input\ unit}} \)

Where the reference values for R are:

kJ/kmol·K: 8.31447
kJ/km³·K: 8.31447
kPa·m³/kmol·K: 8.31447
bar·m³/kmol·K: 0.0831447
L·atm/kmol·K: 82.05
Btu/lbmol·R: 1.98558
ft·lbf/lbmol·R: 1545.37
psia·ft³/lbmol·R: 10.73

Select the input and output units, enter the input value, and calculate the result.

Using the Universal Gas Constant R Unit Converter

This calculator is useful for engineering, chemistry, and physics applications involving the ideal gas law, supporting conversions between SI and imperial units for R.

Select the input unit, output unit, and input the numerical value. The calculator outputs the converted value.

Example 1: Convert 8.31447 kJ/kmol·K to Btu/lbmol·R.

Input Unit: kJ/kmol·K
Output Unit: Btu/lbmol·R
Input: \( 8.31447 \)
Calculation: \( 8.31447 \times (1.98558 / 8.31447) = 1.98558 \)
Result: \( 1.98558 \, \text{Btu/lbmol·R} \)

Example 2: Convert 82.05 L·atm/kmol·K to psia·ft³/lbmol·R.

Input Unit: L·atm/kmol·K
Output Unit: psia·ft³/lbmol·R
Input: \( 82.05 \)
Calculation: \( 82.05 \times (10.73 / 82.05) = 10.73 \)
Result: \( 10.73 \, \text{psia·ft³/lbmol·R} \)

Use this tool for quick unit conversions of the gas constant in scientific analysis.

Common FAQ

Below are frequently asked questions about Universal Gas Constant R unit conversions:

Q: What is the Universal Gas Constant R?
A: R is a physical constant relating pressure, volume, amount of substance, and temperature in the ideal gas law, with values depending on units.
Q: Why do numerical values differ between units?
A: Different unit systems (SI vs. imperial) change the numerical coefficient while representing the same physical constant.
Q: Is kJ/kmol·K the same as kPa·m³/kmol·K?
A: Yes, numerically equal since 1 kJ = 1 kPa·m³.
Q: How accurate is this calculator?
A: It provides precise results based on standard values, rounded to 5 decimal places.
Q: Can negative values be used?
A: No, input values must be positive; invalid inputs leave the result blank.