How to Find Partial Pressure of Gases in a Mixture using Ideal Gas Law?
The pressure that is exerted by a gas in a mixture of gases is termed as the partial pressure. The partial pressure of each gas can be calculated using various methods, where as this tutorial is based on the ideal gas law PV = nRT. Use this simple step by step tutorial to learn how to find partial pressure of gases in a mixture.
Based on Ideal Gas Law,
P = nRT / V
P = Partial Pressure
n = Number of Moles
R = Molar Gas Constant
T = Temperature
V = Volume
Step 1 : Consider a a mixture of 2.00 g of H2 and and 4g of CO2 is added in a 2.0 L of container at a temperature of 298 Kelvin. Find the partial pressure of H2.
Combustion Amount / Volume, V = 2 L.
Temperature, T = 298 K
Molar Gas Constant, R = 8.314 K-1mol-1
Step 2: We have to know the number of moles of H2 to find the partial pressure,
To find number of moles(n),
n = Combustion Amount / Molar Mass
We know, Molar Mass of H2 =2.01588 g/mol
n = 2 / 2.01588
Step 3 :Apply the values in the formula,
P = (0.992 x 8.314 x 298) / 2
= (8.247 x 298) / 2
= 2457.75 / 2
= 1228.87 kPa
Hence, based on the Ideal Gas Law, calculated partial pressure of H2 is 1228.87 kPa