Calculate the partial pressure of CO2. Determine the mole fractions.

Question

(a) A gas mixture contains CO₂ and N₂ in a 15.90 L gas cylinder at 35°C, and the total pressure is 29.75 atm. There is 7.152 mol N₂ in the gas mixture. Calculate the partial pressure of CO₂.

(b)Determine the mole fractions of NO₂, CH_4, and Ne in a sample of gas that contains 1.850 mol of NO₂, 2.29 mol of CH_4, and 3.01 mol of Ne.

Answer 1

Total pressure = partial pressure CO₂ + partial pressure N₂ (Dalton's Law)

Mole fraction x Total pressure = partial pressure of the gas

a.

1). Find total mols of gas present:

PV = nRT and solve for n

n = PV/RT = (29.75 atm)(15.90 L) / (0.0821 Latm/Kmol)(308K)

n = 18.71 mols of gas

2). Find moles of CO₂:

18.706 mols - 7.152 mols N₂ = 11.55 mols CO₂

3). Determine partial pressure of CO₂:

partial pressure CO₂ = mol fraction CO₂ x Total pressure

mole fraction of CO₂ = mols CO₂ / mols CO₂ + mols N₂ = 11.55 mols / 18.706 mls = 0.6177

partial pressure CO₂ = 0.6177 x 29.75 atm = 18.38 atm

b.

1). Find total mols of gas:

Total moles = 1.850 mol NO₂ + 2.29 mols CH₄ + 3.01 mols Ne = 7.15 mols

2). Find mol fraction of each gas:

mol fraction of a gas = moles of gas / total moles

mol fraction NO₂ = 1.85 / 7.15 = 0.259

mol fraction CH₄ = 2.29 / 7.15 = 0.320

mol fraction Ne = 3.01 / 7.15 = 0.421

Answer 2

Hi Ju M.,

You have just submitted multiple (n=3) questions on the same skill set. It is not necessary to submit your entire chemistry homework assignment in order to learn what you need to do. In fact, it is spamming, and NOT what Wyzant is intended for. Tutors will be less likely to answer anything from a student who does this. Please, in the future, submit ONE question on a particular topic (here, use of the Universal Gas Equation), and wait for help.

-- Cheers, --Mr. d.