Final answer:
The molar mass of a gas is calculated by dividing the mass of the gas by the number of moles obtained from the ideal gas law equation (PV = nRT).
Step-by-step explanation:
The molar mass of a gas can be determined by manipulating the ideal gas law, which is presented as PV = nRT where P is pressure, V is volume, n is the number of moles, R is the universal gas constant, and T is temperature. To find the molar mass, we start by measuring the mass (m) of the gas and using the ideal gas law to calculate the number of moles (n) of the gas when the pressure (P), volume (V), and temperature (T) are known. From there, we can find the molar mass by dividing the measured mass by the number of moles (m/n). This technique is useful particularly when you have collected a gas from a chemical reaction and need to determine its identity.