Determination of Gas Constant

Introduction A gas is the state of matter that is characterized by having neither a fixed shape nor a fixed volume. Gases exert pressure, are compressible, have low densities and diffuse rapidly when mixed with other gases. On a microscopic level, the molecules (or atoms) in a gas are separated by large distances and are in constant, random motion. When dealing with gases, the Ideal Gas Law equation is the most famous equation used to relate all the factors in dealing and solving the problem. The four factors or variables for gas are: pressure (P), volume (V), number of mole of gas (n), and temperature (T), and the constant in the equation is R, known as the gas constant. The Ideal Gas law equation which is pV=nRT is obtained by combining the three Gas Laws: Boyle’s Law, Charles’s Law and Avogadro’s Law. Boyle’s Law describes the inverse proportional relationship between pressure and volume at a constant temperature and a fixed amount of gas. Charles's Law describes the directly proportional relationship between the volume and temperature (in Kelvin) of a fixed amount of gas, when the pressure is held constant. Avogadro’s Law describes that volume of a gas is directly proportional to the amount of gas at a constant temperature and pressure. The Ideal Gas equation shows that the volume of a gas is dependent on both pressure and temperature. In comparing volumes of two gases, they must be in the same pressure and temperature known as the Standard Temperature and Pressure, or STP.
The purpose of this experiment is to derive the universal gas constant for gases experimentally by collecting gases from the neutralization reaction and determining the volume and pressure of the gas and then the partial pressure of the gas formed. The single displacement reaction between magnesium metal and hydrochloric acid will be used to generate the hydrogen gas:
Mg (s) + 2 HCl (aq)  MgCl2 (aq) + H2 (g)

Experimental Method In preparing the metal, a two