What is the formula for calculating the partial pressure of a gas?

The correct formula for calculating the partial pressure of a gas is derived from Dalton's Law of Partial Pressures. When calculating the partial pressure, the formula states that the partial pressure of a particular gas in a mixture is equal to the total pressure multiplied by the mole fraction of the gas.

The correct relationship is represented by the formula:

P_a = (n_a / n_tot) x P_tot.

In this equation:

• P_a is the partial pressure of gas A.

• n_a is the number of moles of gas A.

• n_tot is the total number of moles of all gases in the mixture.

• P_tot is the total pressure of the system.

This means that the partial pressure is directly proportional to the number of moles of the specific gas relative to the total number of moles present, scaled by the total pressure.

The other choices do not accurately capture this relationship or mix formulas that do not apply to the calculation of partial pressures. It is essential to understand the contributions of individual gases to the overall pressure of a mixture to apply the correct formula effectively.