Answer:
The partial pressure of methane in the flask is 1.00 atm and the total pressure in the flask is 1.26 atm.
Explanation:
You must apply the Ideal Gases Law to solve this;
Pressure . volume = n° moles . Gases constant (R) . T° in K
T° in K = T°C + 273
72 + 273 = 345K
Gases constant (R) = 0.082 L.atm /mol.K
n° moles = in mixture, the total moles are the sum of each gas.
Moles = mass / molar mass
Moles Ne = 1.56 g / 20.17 g/m = 0.077 moles
Moles CH₄ = 4.85 g/ 16.04 g/m = 0.302 moles
0.077 + 0.302 = 0.379 moles
Pressure . 8.53L = 0.379 moles . 0.082 L.atm /mol.K . 345K
Pressure = ( 0.379 moles . 0.082 L.atm /mol.K . 345K ) / 8.53L
Pressure = 1.26 atm (The total pressure in system)
We can use the molar fraction to know, the partial pressure of CH₄.
Moles CH₄ / Total moles = Partial pressure CH₄ / Total pressure
0.302 / 0.379 = Partial pressure CH₄ / 1.26 atm
(0.302 / 0.379 ) . 1.26 atm = Partial pressure CH₄
1.00 atm = Partial pressure CH₄
