# Determination of the Molar Volume of a Gas and the Universal Gas Constant

2079 Words Mar 19th, 2013 9 Pages
EXPERIMENT NO. 6
DETERMINATION OF THE MOLAR VOLUME OF A GAS
AND THE UNIVERSAL GAS CONSTANT

Salve, Ryan Angelo TAB3, Group 6, Mr. John Kevin Paulo Biadomang Tabor, Frances Hermilyn March 8, 2013
-------------------------------------------------

I. Abstract

This experiment is working with the ideal gas law, which is the summation of Boyle’s Law, where pressure is inversely proportional to volume, Charles’ Law, where the volume is directly proportional to temperature and Avogadro’s Law, where the volume is directly proportional to moles. In this experiment, the volume occupied by one mole of H2 was determined. By measuring the volume of H2 gas generated, its molar volume can also be calculated. The universal gas constant can be
The volume of the gas and the temperature of the water were recorded. The experiment was repeated twice.
V. Results The results of the experiment were shown below.

Table 2 Atmospheric Pressure | 760 mm Hg | Atmospheric Pressure in kPa | 101.308 kPa | Temperature of H2O in beaker | 28°C | Temperature in Kelvin | 301.15 K | Vapor Pressure measured at indicated temperature | 3.77239 kPa | Corrected Pressure of gas in cylinder | 97.53561 kPa |

Table 3. Results of the trials | Trial 1 | Trial 2 | Trial 3 | Average | Volume of gas (L) | 0.0056 | 0.0064 | 0.0062 | 0.0061 | Length of Mg ribbon reacted (cm) | 0.4 | 0.4 | 0.4 | 0.4 | Mass of Mg ribbon reacted (g) | 0.0057 | 0.0062 | 0.0056 | 0.0058 | Moles of Mg used (mol) | 2.34 x 10-4 | 2.55 x 10-4 | 2.30 x 10-4 | 2.39 x 10-4 | Moles of H2 produced (mol) | 2.34 x 10-4 | 2.55 x 10-4 | 2.30 x 10-4 | 2.39 x 10-4 | Ratio of volume of gas generated to moles of gas produced, V/n | 23.93 L/mol | 25.10 L/mol | 26.96 L/mol | 25.33 L/mol | Universal gas constant (kPaV/nT) | 7.75 kPa∙Lmol∙K | 8.08 kPa∙Lmol∙K | 8.73 kPa∙Lmol∙K | 8.19 kPa∙Lmol∙K |

VI. Discussion To determine the pressure of H2 in the cylinder, the vapour pressure of the water was subtracted from the atmospheric pressure. This formula was derived from Dalton’s Law of partial pressure, Ptotal=Pgas+PH2O
The partial pressure of water vapour depends on the temperature of the water bath. To obtain the partial