### Dalton’s Law of Partial Pressure Calculator:

Enter the Dalton’s law Total pressure in kPa, Mole fraction Partial pressure kPa, Ideal gas law in Temperature in °C, Volume in m³, Partial pressure in kPa, and Henry’s law – method 1 in Gas in oxygen, Concentration in M, Partial pressure in kPa.

### Dalton’s Law Formula:

Dalton’s law formula is partial pressure of the ideal gas mixture P_{total} is equal to the partial pressure of the nitrogen P_{N2 }and addition the partial pressure of the hydrogen PH_{2} and addition partial pressure of the oxygen P o_{2.}Hence the Dalton’s law formula can be written as

P_{total = }P_{N2} + PH_{2} +P o_{2}

### Derivation:

P_{total = }partial pressure of the ideal gas mixture

P_{N2 = }partial pressure of the nitrogen

PH_{2} = partial pressure of the hydrogen

P o_{2} = partial pressure of the oxygen

### Formula of Mole Fraction:

Xi = ni /n_{total}

Xi = mole fraction

Ni =number of moles of an individual gas constituent of the mixture

N_{total} =total number of moles of all constituents of the mixture

Mole fraction is also called amount fraction

Relationship between mole fraction and partial pressure for ideal gases

Mole fraction of an individual gas component of an ideal gas mixture can be expressed as

X_{i} = n_{i} /n…..(1)

Where n is the number of moles of an individual gas of the ideal gas mixture

N =total number of moles of all constituents of the ideal gas mixture

Xi =mole fraction

Xi = p_{i} /p …..(2)

P_{i}= partial pressure of an individual gas in the ideal gas mixture

P = total pressure of the ideal gas mixture

X_{i} = mole fraction

From equation (1) and (2) we can write

X_{i} =n_{i} / n = p_{i} /p

So partial pressure of an individual gas of the ideal gas mixture can be expressed as

P_{i} =x_{i} *p

Now as we know mole fraction of gas component in a gas mixture is equal to its volumetric fraction in the gas mixture, so we can write

N_{X }/ n_{total} = px / p_{total }= vx/ v_{total}

when nx =moles of the gas component x

n_{total} = total number of moles of all components of the mixture

px = partial pressure of gas x

p_{total} =total pressure of the gas mixture

vx = partial volume of any individual gas component x

v_{total} = total volume of the gas mixture

### Example:1

Calculate the mixture of hydrogen gas and oxygen gas exerts a total pressure of 1.8 atm, partial pressure of hydrogen is 2 atm.

### Answer:

Given

p_{hydrogen} =2 atm, p_{total }=1.8 atm

Applying Dalton’s law formula P_{total} =P_{hydrogen }+P_{oxygen}

Therefore P_{oxygen} =0.8atm

Now the mole fraction of X_{oxygen } =(P_{oxygen }/ P_{total}) =0.8/1.8=0.44

Therefore, the mole fraction of oxygen in the mixture is 0.44

### Example:2

Calculate the mixture of hydrogen gas and oxygen gas exerts a total pressure of 1.3 atm on the walls of its container. In partial pressure of hydrogen is 4 atm.

### Answer:

Given

p_{hydrogen} =1 atm, p_{total }=1.5 atm

Applying Dalton’s law formula P_{total} =P_{hydrogen }+P_{oxygen}

Therefore P_{oxygen} =0.5atm

Now the mole fraction of X_{oxygen } =(P_{oxygen }/ P_{total}) =0.5/1.5=0.33

Therefore, the mole fraction of oxygen in the mixture is 0.33