# The gas laws

## Gas laws and the simple kinetic theory of matter

Gas laws and the simple kinetic theory of matter An introduction to the kinetic theory of matter has been given in chapter 13. On this theory a gas consists of a vast number of molecules moving with random high velocities, colliding with one another, and bouncing off the walls of the containing vessel. A force is thus …

## Reduction of gas volumes to standard temperature and pressure

Reduction of gas volumes to standard temperature and pressure In certain chemical experiments a volume of gas is collected at room temperature and pressure, and it is necessary to calculate the volume which the gas would occupy at 0 °C and 760 mmH ressure. 0 °C and 760 mmHg are called standard temperature an pr~ usual y abbreViated.

## Pressure law

Pressure law The pressure of a fixed mass of gas at constant volume is proportional to its thermodynamic temperature.  The relation between Summarizing the gas laws dealt with in this chapter we have pressure, volume and thermodynamic temperature pV = constant (Boyle’s law) TV = r constant (Charles’s law) Tp’= V constant (Pressure law) These three equations …

## Charles’s law

Charles’s law The volume of a fixed mass of gas at constant pressure is proportional to its thermodynamic temperature.

## Other ways of expressing Charles’s law and the Pressure law

Other ways of expressing Charles’s law and the Pressure law If we assume that the two graphs in Figs. 16.8 and 16.9 have been plotted using Celsius and thermodynamic temperatures then we can use them to express Charles’s law and the Pressure law in a form which is usually more convenient for calculation purposes than the …

## The absolute or thermodynamic scale of temperature

The absolute or thermodynamic scale of temperature If volume-temperature and pressure-temperature graphs for a gas are plotted on extra large sheets of graph paper and then produced or extrapolated backwards they cut the temperature axis at – 273°C (Fig. 16.8 and 16.9). This suggested to the early experimenters that – 273°C might be the lowest temperature attainable …

## To measure the pressure expansivity of air

To measure the pressure expansivity of air The apparatus for this experiment was designed by the German professor of physics, Philipp Jolly, who lived during the nineteenth century. It is generally called the simple constant volume air thermometer (Fig. 16.7). A glass bulb B joined to a capillary tube is connected to a mercury reservoir R by a …

## Pressure expansivity of a gas at constant volume

Pressure expansivity of a gas at constant volume It now remains to investigate the manner in which the pressure of a gas varies when it is heated at constant volume. The pressure expansivity of a gas at constant volume is defined as the fraction of its pressure at 0 °C by which the pressure of a fixed …

## To measure the cubic expansivity of air at constant pressure

To measure the cubic expansivity of air at constant pressure A glass tube about 30 em long and about 1.5 mm bore has one end sealed by heating in a bunsen flame. A short pellet of concentrated sul phuric acid is then introduced a little more than a third of the way down the tube by means …

## Cubic expansivity of a gas at constant pressure

Cubic expansivity of a gas at constant pressure It may be remembered that when the linear expansivity of a solid was defined on page 162 it was not specified that the original length of the rod of material should be measured at 0 “C. Owing to the smallness of the linear expansion of most substances, it makes …