Calculate the Molar Mass of a Vapor using Ideal Gas Law

How can we calculate the molar mass of a vapor using the ideal gas law?

In the given data, what are the key parameters that we need to consider?

Calculation of Molar Mass using Ideal Gas Law:

To calculate the molar mass of a vapor using the ideal gas law, we can follow these key steps:

  1. Convert the volume of the flask from milliliters to liters.
  2. Convert the temperature from Celsius to Kelvin.
  3. Use the ideal gas law equation: PV = nRT to solve for the moles of the vapor.
  4. Divide the mass of the substance by the number of moles to calculate the molar mass of the vapor.

Explanation:

Calculating the molar mass of a vapor using the ideal gas law involves utilizing the pressure, volume, and temperature of the vapor. In the provided data, the pressure is given as 751 mm Hg, the volume of the flask is noted as 234.46 mL, and the temperature is 100°C.

Firstly, we need to convert the volume of the flask from milliliters to liters. By dividing the volume by 1000, we get 0.23446 liters. Next, the temperature needs to be converted from Celsius to Kelvin by adding 273.15, resulting in 373.15 K.

Using the ideal gas law equation PV = nRT, where P represents pressure, V is volume, n stands for moles of the substance, R is the ideal gas constant, and T denotes temperature in Kelvin, we can calculate the number of moles of the vapor, which is 0.0199 moles in this case.

Finally, to determine the molar mass of the vapor, we divide the mass of the substance, which is 49.230 g, by the number of moles. The result is 2471.36 g/mol as the molar mass of the vapor.

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