The state of actual gas and the law of partial pressure of gas

When the mutual attraction between gas molecules and the volume of the gas molecules themselves are not negligible, the ideal gas state equation is no longer applicable
.

When the mutual attraction between the gas molecules can not be ignored over, the gas pressure p over the same amount of material than the actual pressure p of the gas molecules collide with the wall produced by _treatment of small, adding a correction term p need _repair
.

p _rationale = p + p _repair

Research shows that the correction term p _repair is proportional to n ² and inversely proportional to V ²
.

When the volume of the actual gas molecule itself is not negligible, only by subtracting the volume of the molecule itself from the volume V of the actual gas can the free space equivalent to the ideal gas be obtained (that is, the gas molecules can move freely and the volume can be compressed infinitely)
.

V _theory =V-nb

Substituting the above correction term into the ideal gas state equation to obtain the actual gas state equation

The state equation of the actual gas is proposed by van der Waals, so it is called the van der Waals equation
.

1.
1.
3 The law of partial pressure of gases

1.
Partial pressure and volume

The gas formed by mixing two or more gases is called a mixed gas, and each gas that makes up the mixed gas is called a component gas of the mixed gas
.

pV=nRT

When a certain component gas exists alone and occupies the total volume, it is called the partial pressure of the component gas, represented by Pi, then

p _i V=n _i RT

In the formula, V is the volume occupied by the mixed gas; n _i is the amount of substance in a certain grade of gas
.

The volume occupied by a certain component gas i when it exists alone and has a total pressure P is called the sub-volume of the component gas, denoted by Vi, then

pV _i = n _i RT

2.
Mole Fraction

Amount amount of substance which contains a mixed gas of a composition of the gas mole fraction is called fraction, with X _I expressed
.

From the ideal gas equation of state, when p and T are constant, the mole fraction of a certain component gas in the mixed gas is equal to the volume fraction (the fraction of the partial volume of a certain component gas in the total volume of the mixed gas)
.

3.

The total pressure of the mixed gas is equal to the sum of the partial pressures of each component gas, which is called the gas partial pressure law, also known as the Dalton partial pressure law
.

P = ∑p _i

Divide p _i V=n _i RT by pV=nRT.

which is

p _i =px _i

This is an important conclusion of the gas partial pressure law.