by Amelia Wagoner

Created on: March 10, 2007   Last Updated: May 02, 2007

Introduction
An important area of physical chemistry would be the kinetic theory of gases. The kinetic theory of gases was developed over a long period of time that also included the important involvement of the gas laws (Laider 131). The two gas laws involved are Boyle's law and Gay-lussac's law also known as Charles's law. Boyle's law states that "the volume of a given quantity of a gas varies inversely as the pressure, the temperature remaining constant" (Barrow 3) in other words:

PV=constant.
Gay-Lussac's law defines the relationship between temperature and gas volume. It states "the volume of a given mass of gas varies directly as the absolute temperature if the pressure remains constant" (Barrow 6).
V/T= constant
Temperature in this case does not refer to degrees in Celsius. Instead the absolute Kelvin temperature scale is used. The Kelvin scale begins at absolute zero and has a value of -273.15 degrees in Celsius. When either volume or pressure of a gas was varied with temperature using Celsius it was found that the lowest temperature reached was consistently -273.15. Since this was the lowest temperature possible, it made since to then reset this temperature as zero for the Kelvin scale (Huestis 70).
To better understand why the gas laws behave as they do one should also consider some of the properties present in all gases. These properties are: gases can be compressed, gases exert pressure on whatever surrounds them, gases expand into whatever volume is available, and temperature, pressure, volume occupied, and amount present is taken into account when referring to gases (Moore 437-8). Taking in consideration these properties and the gas laws Avogadro then came up with an equation that can be related to all gases and uses a universal constant. He did this by defining and incorporating the base unit of the mole (n), and combing the other gas laws (Laidler 134-135). This single equation he came up with is the most commonly used and is referred to as the Ideal Gas Law.
pV=nRT
The objective of this experiment is to show Gay-Lussac's law pertains to real gases in a laboratory environment, how the ideal gas law can still be used for gases that are not completely ideal and how absolute zero can be estimated (Huestis 70).
Experimental
For the gas laws and absolute zero lab the temperature inside the tube containing the smaller tube and dibutyl phalate was recorded as an initial temperature. The thermometer used to record the temperature had a precision of + 0.2

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