## The Gas and laws

The Gas and laws Described here:

### Ideal gas

1) It is the gas which strictly obeys gas laws, like Boyle’s law, Charles’s law etc.
2) For ideal gas, the size of the gas molecules is zero and the volume of the gas molecule is also zero.
3) There is no face of attraction or repulsion amongst the molecules of an ideal gas.
4) Molecules of an ideal gas have only kinetic energy.
5) The ideal gas cannot be liquefied or solidify, which supports the absence of inter molecular forces of ideal gas.
6) Internal energy of an ideal gas in independent of volume.
7) The internal energy of an ideal gas depends upon the temperature.
8) No gas available in the universe is strictly an ideal gas.
9) The gas such as Hydrogen, Oxygen, Nitrogen and mono-atomic insert gases behave very similar to ideal gases.
10) Real gases at low temperature behave as ideal gases.
11) Real gases obey gas equation i.e. PV = nRT.

### Real gases

1) The gases which are actually found in nature are called real gases.
2) The size of the molecules of a real gas is finite and hence the volume of the molecules of a real gas is finite.
3) There is a force of attraction or repulsion between the molecules of a real gas. The intermolecular force between molecules is attractive for large intermolecular separation and repulsive for small intermolecular separation.
4) The molecules of a real gas have potential energy as well as kinetic energy.
5) The internal energy of a real gas depends on pressure, volume and temperature of the gas.
6) The real gas can be liquefied.
7) In vander waal’s equation, the value of a depends upon the intermolecular force and the nature of the gas.
8) Real gases do not obey the gas laws at all temperatures.

### Gram mole or kilogram mole

1) The molecular weight expressed in the gram is called gram mole (g.mole). The molecular weight expressed in kilograms is called kilogram mole (kg.mole).
2) The mass of 1 mole of gas is equal to its molecular weight in gram. And 1kg mol = 1000 g.mole.
3) For Example, one gram mole of hydrogen gas is 2 gram and 1 kilogram mole of hydrogen is 2 k. Therefore in 2 kg hydrogen gas, the amount of hydrogen is 1000 moles.

### Boyle’s law

It states that the volume V of the given mass of a gas is inversely proportional to its pressure P, when temperature is kept constant i.e. V is praportional to 1/P or V = K/P or PV=K=a constant.

### Charle’s law

It states that the pressure remaining constant, the volume of the given mass of a gas is directly proportional to its Kelvin temperature i.e. V is praportional to T if P is constant.

### Standard gas equation

PV = nRT Where n is the number of moles contained in the given ideal gas of volume V, Pressure P and temperature TK.

### Absolute zero

1) It is that the temperature at which the root mean squire velocity of the gas molecules reduces to zero.
2) Since the temperature of a gas is directly proportional to the squire of the r.m.s velocity of the gas molecules.
3) Room means squire velocity of the molecules of a gas depends on temperature alone and is independent of mass of the molecule.
4) Roots mean square velocity of the molecules of a gas is independent of the volume and pressure of the gas.