7. What is the total pressure of the following mixture of gases in a 20.0 L container at 298 K: 12.0 g He,

4.00 mol H2 and 6.25 atm Ne?

P (total) = 14.81 atm

Explanation:

According to the Dalton law of partial pressure,

The pressure exerted by mixture of gases are equal to the sum of partial pressure of individual gases.

P (total) = P1 + P2 + P3 + ... + Pn

Given dа ta:

Volume of container = 20.0 L

Temperature = 298 K

Mass of He = 12.0 g

Moles of hydrogen = 4.00 mol

Pressure of Ne = 6.25 atm

Solution:

Moles of helium:

Number of moles = mass/molar mass

Number of moles = 12 g / 4 g/mol

Number of moles = 3 mol

Pressure of helium:

PV = nRT

P = nRT / V

P = 3 mol * 0.0821 atm. L. mol⁻¹. k⁻¹ * 298 K / 20 L

P = 73.4 atm / 20

p = 3.67 atm

Pressure of hydrogen:

PV = nRT

P = nRT / V

P = 4 mol * 0.0821 atm. L. mol⁻¹. k⁻¹ * 298 K / 20 L

P = 97.86 atm / 20

P = 4.89 atm

Total pressure:

P (total) = P (He) + P (Ne) + P (H₂)

P (total) = 3.67 atm + 6.25 atm + 4.89 atm

P (total) = 14.81 atm