 In the Dunmah method of determining the molar mass of a volatile liquid, we will start out massing an empty 125 milliliter Erlenmeyer flask, a small piece of aluminum foil, and a small piece of copper wire. We will then add approximately 5 milliliters of the unknown liquid. We will cover the mouth of the flask with the aluminum foil. We will use the copper wire to hold the aluminum foil in place. We will place a small pinhole in the top of the aluminum foil. We immerse the flask in a beaker of boiling water. The liquid inside the Erlenmeyer starts to boil and vaporizes. As it vaporizes, it pushes air out of the pinhole. Eventually, all the liquid vaporizes and the flask is filled with just enough vapor to fill the flask at the temperature of the boiling water. Once the liquid has completely vaporized and the vapor has reached the temperature of the water bath, we will remove the flask from the water bath. The vapor inside the flask will condense to a liquid. When the flask is cooled to room temperature, the liquid that has condensed was the amount of vapor that would fill the flask at the temperature of the boiling water bath. We will now mask the flask, the liquid, the aluminum foil, and the copper wire. Since we know the mass of the empty flask, aluminum foil, and copper wire, we can get the mass of the liquid. We will determine the volume of the flask, which is also the volume which the vapor occupied at the temperature of the boiling water bath. We will remove the copper wire and the aluminum foil. We will fill the flask completely with water, and we will pour the water into a graduated cylinder. We will record the volume of the water.