A volatile liquid can be easily converted to its gaseous state, the gas that forms from vaporization is known as vapor and it is assumed to behave as an ideal gas. One of the properties that characterize a volatile liquid is determination of its molar mass. Dumas method also known as the vapor density method uses the vapor density of the unknown volatile liquid in determining its molar mass. The major assumptions of these methods are the substance behaves ideally. The molar mass of a volatile liquid can be obtained by measuring the temperature, pressure, mass, and volume in a gaseous state. The equation used to determine the molar mass is derived from the Ideal Gas Law equation. The objective of this experiment aims to determine the molecular mass of a …show more content…
In order to calculate for the molar mass the temperature, volume, mass, and pressure was measured. The ideal gas law equation was derived in order to express the relationship between the molar mass, mass of the condensate, temperature, pressure, and volume. A 125-mL Erlenmeyer flask was added with an unknown liquid, was capped with an aluminum foil with a tiny hole and was heated in boiling water in a beaker until the liquid in the flask is vaporized. The flask was cooled until condensate is observed. After cooling, the flask was weighed in an analytical balance. The experimental molar mass was 45.56g, which is closely identical to the 46.068g of the molar mass of ethanol. The percent error between the two values is 1.10%, the probable sources of error are the following: the size of the tiny hole in the aluminum foil, measurement of the temperature in the thermometer, and measurement of the initial volume of the flask. The recommendation for the experiment is to dry the flask completely before measuring the initial mass and to closely observe if the temperature of the water bath is