Final answer:
To find the molar mass of an unknown compound, we use the ideal gas law, PV=nRT. We calculate the number of moles using the given pressure, volume, temperature, and the gas constant R. Then, we divide the known mass of the gas by the calculated number of moles to get the molar mass.
Step-by-step explanation:
To explain how to find the molar mass of the unknown compound, we first use the ideal gas law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature. The molar mass (MM) is the mass of one mole of a substance. By rearranging the ideal gas law, we can find the number of moles (n = PV / RT) and then the molar mass (MM = mass/n).
Inserting the known values: P = 1.22 atm, V = 0.245 L (from 245 mL), T = 298 K, and mass = 0.538 g, we can calculate the molar mass of the compound. We use the gas constant R = 0.0821 L·atm/mol·K.
First, find the number of moles: n = PV / RT = (1.22 atm)(0.245 L) / (0.0821 L·atm/mol·K)(298 K).
Then, find the molar mass: MM = mass / n = 0.538 g / n.
The calculated molar mass would provide information about the identity of the compound when compared to known substances.