Partial pressure calculator

Place required values in input boxes below to use Partial pressure calculator.

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Partial pressure formula

Dalton's law

Ptot = p1 + p2 + p3 +...+ pm

Partial pressure = total pressure × mole fraction

Ideal gas law

p × V = n × R × T

For partial pressure of one component,

pi = (ni × R × T)/v


Ptot is the total pressure,
p1, p2, p3,..., pm is the partial pressures of the individual gases in the mixture,

Mole fraction is number of moles of individual gas divided by total number of moles in gas,
V is volume,

T is temperature,

pi is the partial pressure of the individual gas,

n is the number of moles of the gas,

ni is the mount of moles of the individual gas, and

R is ideal gas constant with a value of 8.314 J K-1 mol-1.

The Dalton’s law calculator finds the movement of gas in a solution. It takes moles of gases, volume, and temperature from user to find the partial pressure of gases in the mixture. Pressure calculator is widely used in chemistry for pressure of gas calculation.

Let’s go through partial pressure (Dalton’s law) definition, how to find partial pressure without using total pressure calculator, partial pressure equation, and some examples of Dalton’s law of partial pressure.

What is partial pressure?

Dalton's law of partial pressure measures total pressure using temperature, moles of gas and volume.

Dalton’s Law states the principle that the pressure exerted by a mixture of gases in a fixed volume is equal to the sum of the pressures that each gas would exert if it occupied the whole volume.

How to calculate partial pressure?

You can find partial pressure easily by using partial pressure of gas calculator, however, you should also know how to calculate partial pressure of gas manually. Let’s calculate the partial pressure using an example.

Example: Dalton’s law

Find the partial pressure of Helium if a mixture of 4 mol He and 3 mol H2 exerts a total pressure of 5 kPa.


Step 1: Write down the values.

He = 2 mol

H2 = 3 mol

Total pressure = 5 kPa

Step 2: Calculate the mole fraction for Helium.

Mole fraction He = Number of moles of He/Total moles in gas

Mole fraction He = 2/5

Step 3: Use the Dalton’s law equation to find the partial pressure.

Partial pressure = total pressure × mole fraction

Partial pressure = 5 × 2/5

P = 2 kPa

Example: Ideal gas law

Find the partial pressure of 2 moles of Neon if temperature of gas is 200 K, volume is 5 L.


Step 1: Write down the values.

n = 2 mol

T = 200 K

V = 5 L

Step 2: Use the Ideal gas law equation.

pi = (ni × R × T)/v

pi = (2 × 8.314 × 200)/5 Since R = 8.314 J K-1 mol-1

pi = 665.12 kPa

Verify value of partial pressure using Dalton’s law of partial pressure calculator.


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