conditions of temperature and pressure (abbreviated as STP). The standard
pressure is defined as the height of mercury that can be held in an evacuated tube
by 1 atmosphere of pressure (14.7 lb/in.^2 ). This is usually expressed as 760
millimeters of Hg or 101.3 pascals. Standard temperature is defined as 273
Kelvin or absolute (which corresponds to 0° Celsius).
Charles’s Law
Jacques Charles, a French chemist of the early nineteenth century, discovered that,
when a gas under constant pressure is heated from 0°C to 1°C, it expands 1/273
of its volume. It contracts this amount when the temperature is dropped 1 degree
to −1°C. Charles reasoned that, if a gas at 0°C was cooled to −273°C (actually
found to be −273.15°C), its volume would be zero. Actually, all gases are
converted into liquids before this temperature is reached. By using the Kelvin
scale to rid the problem of negative numbers, we can state Charles’s Law as
follows:
If the Pressure Remains Constant, the Volume of a Gas Varies Directly as the
Absolute Temperature. ThenTIP
Charles’s Lawat constant pressure is a direct proportion.