## Degrees of freedom

Number of degrees of freedom of a system is given by following,
N = 3A – R
Where,
A is the number of particles in the system and R is the number of independent relations among the particles.

For mono atomic gases, the degrees of freedom is three.
For diatomic gases, the degrees of freedom is five.
Linear triatomic molecules has seven degrees of freedom.
A non Linear triatomic molecules has six degrees of freedom.

## Specific heat capacity

Specific heat capacity is given by,

$$s = \frac{S}{m}$$

Where, S is heat capacity and $latex m$ is the mass of substance.

The unit of specific heat capacity is J kg-1 k-1

## What is the ideal gas equation?

The equation of state of an ideal gas is given by,

PV = nRT

Where, n is the number of moles of the gas and R is the gas constant for one mole of the gas.

### The gas law

#### Boyle’s law

If $$\mu$$ and T are constant then idael gas equation becomes, $$PV = Constant$$ or $$P \propto \frac{1}{V}$$ This is the Boyle’s law.

#### Charle’s law

If $$\mu$$ and P are constant then idael gas equation becomes,
$$V \propto T$$ This is the Charle’s law.

#### Gay lussac’s law

If $$\mu$$ and V are constant then idael gas equation becomes,
$$P \propto T$$

This is the Gay lussac’s law.