Question

1. there are 2.0 moles of hydrogen, 3.0 moles of nitrogen and 5.0 moles of fluorine in a sealed container. the total pressure is 20.0 atmospheres. what is the partial pressure of the f2, in atmospheres? a) 6.0 atm b) 10.0 atm c) 4.0 atm d) 20.0 atm e) 14.0 atm

Explanation:

Step1: Calculate mole fraction of $F_2$

The total number of moles $n_{total}=2.0 + 3.0+5.0=10.0$ moles. The mole - fraction of $F_2$, $X_{F_2}=\frac{n_{F_2}}{n_{total}}=\frac{5.0}{10.0}=0.5$.

Step2: Calculate partial pressure of $F_2$

According to Dalton's law of partial pressures, $P_{F_2}=X_{F_2}\times P_{total}$. Given $P_{total} = 20.0$ atm. So $P_{F_2}=0.5\times20.0$ atm.

Answer:

B. 10.0 atm