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Gas temperature and pressure (Absolute Zero (the kelvin temperature scale…
Gas temperature and pressure
Particles and pressure
The particles in a gas are far apart from each other and can move around quickly
The temperature of a gas is a measure of the average
kinetic energy
of the particles in the gas.
the faster the average speed of the particles, the higher the temperature.
heating a gas increases the kinetic energy of the particles, so they move faster and the temperature rises.
The pressure of a gas is due to forces on the walls of a container caused by the moving particles hitting the walls.
The faster the particles are moving the more frequent the collisions may be and the more force they will exert when they collide.
Increasing the temperature of a gas increases the speed at which the particles move at, so it also increases the pressure of the gas.
For a fixed mass of gas in a fixed volume, the pressure increases when the temperature increases.
The units for pressure are
pascals (Pa)
, where 1 Pa = N/m2
Absolute Zero
This diagram
shows how the pressure of a fixed volume of gas changes with temperature.
The measurements cannot continue below the boiling point of the substance, as the gas will condense to form a liquid
However, the same graph is obtained for all gases, and if the lines are extended to colder temperatures they meet the horizontal axis -273 C.
Hot.............Cold
The temperature of -273 C is called absolute zero.
if a gas could be made this cold its pressure would be zero and the particles would not be moving
the
kelvin temperature scale
measures temperatures relative to absolute zero.
The units are
kelvin (K)
, and 1 K is the same temperature intervals as 1 C.
Absolute zero is 0 K on this scale
To convert kelvin to degrees Celsius, subtract 273
To convert degrees Celsius to kelvin, add 273
the average kinetic energy of the particles in a gas is directly proportional to the kelvin temperature of the gas.
