Question

partial pressure

1. determine the partial pressure of each gas as shown in the figure below. note: the relative numbers of each type of gas are depicted in the figure.

1 atm
he
ne
ar

Explanation:

Step1: Count the number of each gas

Count the number of He, Ne and Ar atoms in the figure. Suppose there are 4 He atoms, 3 Ne atoms and 2 Ar atoms. The total number of gas atoms is $4 + 3+2=9$.

Step2: Use the mole - fraction formula for partial pressure

The partial pressure of a gas $P_i$ in a mixture is given by $P_i = X_iP_{total}$, where $X_i$ is the mole - fraction of the gas and $P_{total}$ is the total pressure of the gas mixture. Here $P_{total}=1$ atm.
For He: $X_{He}=\frac{4}{9}$, so $P_{He}=\frac{4}{9}\times1\ atm=\frac{4}{9}\ atm\approx0.44$ atm
For Ne: $X_{Ne}=\frac{3}{9}=\frac{1}{3}$, so $P_{Ne}=\frac{1}{3}\times1\ atm=\frac{1}{3}\ atm\approx0.33$ atm
For Ar: $X_{Ar}=\frac{2}{9}$, so $P_{Ar}=\frac{2}{9}\ atm\approx0.22$ atm

Answer:

$P_{He}\approx0.44$ atm, $P_{Ne}\approx0.33$ atm, $P_{Ar}\approx0.22$ atm