Question

14. A sample containing a mixture of Oz, N2, H2 gases has a volume of 42.0 L and is held at a

temperature of 301 K. If the total pressure of the sample is 104 kPa and the partial pressures of
N2 and H2 are 60.0 kPa and 28 kPa respectively, calculate the number of moles of Oz that there
are in the sample. *
Could someone answers this please :)))

Answer 1

0.269 moles of O₂

Step-by-step explanation:

One of the laws from gases states that sum of partial pressures in a mixture determines the total pressure of the system.

Total pressure = 104 kPa

N₂ pressure + H₂ pressure + O₂ pressure = 104 kPa

O₂ pressure = 104 kPa - 60 kPa - 28 kPa → 16 kPa

Let's define the total moles from the mixture by the Ideal Gases Law

We convert 104 kPa . 1atm/ 101.3 kPa = 1.03 atm

P . V = n . R . T

1.03 atm . 42L = n . 0.082 . 301K

(1.03 atm . 42L) / (0.082 . 301K) → n = 1.75 moles

That's the total moles from the mixture. We apply mole fraction to calculate the number of moles of oxygen

O₂ pressure / Total pressure = moles of O₂ / Total moles

16 kPa / 104 kPa = moles of O₂ / 1.75 mol

(16 kPa / 104 kPa ) . 1.75 mol = moles of O₂ → 0.269