# Molar Mass of Gas Calculator

mol
g/mol

The molar mass of a gas is the mass of one mole of the gas, usually expressed in grams per mole (g/mol). The molar mass can be calculated from the ideal gas law, which states that the pressure, volume, and temperature of an ideal gas are related by:

PV = nRT

where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant (8.31 J/molK), and T is the temperature in kelvins.

By rearranging this equation and dividing both sides by n, we can obtain an expression for the molar volume of a gas:

V = RT / P

The molar mass can then be calculated as the ratio of the mass of the gas to the number of moles:

M = m / n

where m is the mass of the gas.

For example, if a gas has a volume of 0.5 L at a pressure of 1 atm and a temperature of 25°C, the molar mass can be calculated as follows:

First, convert the temperature to kelvins: T = 25 + 273.15 = 298.15 K

Next, calculate the moles of gas: n = m / M = PV / RT = (1 atm) (0.5 L) / (8.31 J/molK) (298.15 K)

Finally, divide the mass of the gas by the number of moles to find the molar mass: M = m / n

The molar mass of a gas is a fundamental property that provides information about the composition and behavior of the gas. For example, it can be used to calculate the density of a gas, or to predict its behavior in chemical reactions.