Ideal gases Flashcards
what is the concept of an ideal gas used for
It was developed as a rough estimation that may be used to simulate and predict the behaviour of real gases.
what is an ideal gas
An ideal gas has identical particles of zero volume, with no intermolecular forces between them. The atoms or molecules in an ideal gas move at the same speed.
what are the rules for an ideal gas
- The particles are identical in all ways.
- Their molecules occupy no volume.
- They have no intermolecular forces between the molecules.
- The collisions between the particles and the walls of the container are perfectly elastic (which means that they do not lose energy).
the molecules must follow these rule in order to be seen as an ideal gas
where do we find ideal gases
Ideal gases do not exist in the real world!
Real gases behave more or less like ideal gases except at high pressures and low temperatures.
The real gases that behave the closest to ideal gases are H2and He
what is pressure
Pressure is the force applied over an area
large surace area = low pressure
small surface area = high pressure
in gases The pressure is caused by the collisions of the gas particles on the side of the container. More collisions of the particles will result in a higher pressure.
The unit for pressure is Pa
1 pascal is a pressure of one newton per square metre or N.m^-2
how much is 1 Pascal of pressure
For you to get a feel for 1 pascal of pressure, it is roughly the same as the pressure exerted by one piece of ordinary A4 paper placed on a table. It is not a big force per unit area and that is why we very often measure pressure in kPa or MPa or even GPa.
what is atmospheric pressure
The air surrounding you is made of molecules, and although each molecule is very, very light, the combined effect is that billions and billions of molecules push against everything they come into contact with. Atmospheric pressure, or air pressure, is the name given to this pressure. The air above a surface exerts a force on it as gravity pulls it to Earth. We measure atmospheric pressure at sea level because the level of the sea around the world is constant. The higher you are above sea level, the lower the atmospheric pressure.
what is temperature
Heat and temperature are not the same thing. Heat is a form of energy, and describes the transfer of thermal energy between molecules. Its unit is Joules.
Temperature is how hot or cold something is or even better, describes the average kinetic energy of molecules in a system. It is measured in Celsius (°C), Kelvin(K) or Fahrenheit (°F) as is used in the United States of America.
It is the average kinetic energy of the **particles.
The faster the particles move, the more kinetic energy they have and therefore the higher the temperature.
what is absolute zero
Although temperatures can vary widely, as you saw above, the coldest temperature we can go to is-273 °Cwhich is calledabsolute zero. At this point all substances are solid and the particles stop vibrating. In this and next module, we will be using the Kelvin temperature scale so you will need to know how to convert from degree Celsius to kelvin and back again.
what is volume
Volumeis how much space an object or substance takes up.
Mostly the space is measured in m^3but it could also be mm^3, cm^3or even dm^3.
when do real gases deviate from ideal gases
Real gases deviate from the behaviour of ideal gas at very high pressures and very low temperatures.
what is the pressure of an ideal gas compared to a real gas
the pressure of a real gas is higher than it would be for an ideal gas
this is because When the pressures are really high and the molecules are compressed, the volume will decrease. The volume will approach a very small number but will not be zero because the molecules will occupy some space that cannot be compressed further.
