Partial Pressure & Mole Fractions

Dalton's Law of partial pressure states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of different gases within the mixture.

Mole Fractions

What this means is that if you find the mole fraction of a specific gas, you can find its partial pressure. To find the mole fraction of a gas xa, find n_a which is the moles of the gas in the mixture, then divide it by n_t which is the total number of moles in the gas mixture. This will give you the mole fraction, and when multiplied by the total pressure, it will give you the partial pressure of the specific gas.

This is shown above in P_A = x_AP_T where P_A is the partial pressure of gas A, x_A is the mole fraction of gas A, and P_T is the total pressure of the gaseous mixture.

Standard Temperature & Pressure

STP or Standard Temperature and Pressure refers to standard measurements or conditions for experimenting with gases. 1 mole at STP is 22.4 liters (Volume), while the temperature is 273 °K, and the pressure is 1 atmosphere.