Answer:
The gas mixture contains 1.038 grams of helium
Explanation:
<u>Step 1:</u> Data given
Volume of the flask = 7.91 L
Total Pressure = 1.42 atm
Temperature = 33 °C
Mass of CO2 = 8.25 grams
Molar mass of CO2 = 44.01 g/mol
Molar mass of He = 4 g/mol
<u>Step 2</u>: Calculate total number moles of gas
p*V = n*R*T
⇒ p = the pressure = 1.42 atm
⇒ V = the volume = 7.91 L
⇒ n= the number of moles = TO BE DETERMINED
⇒ R = the gas constant = 0.08206 L* atm/K*mol
⇒ T = the temperature = 33 °C = 306 Kelvin
n = (p*V)/(R*T)
n = (1.42*7.91)/(0.08206 * 306)
n = 0.447 moles
<u>Step 3</u>: Calculate moles of CO2
Moles CO2 = mass CO2 / Molar mass CO2
Moles CO2 = 8.25 grams / 44.01 g/mol
Moles CO2 = 0.1875 moles
<u>Step 4:</u> Calculate moles of Helium
Moles Helium = total moles of gas - moles of CO2
Moles Helium = 0.447 - 0.1875 = 0.2595 moles of helium
<u>Step 5: </u> Calculate mass of helium
Mass of helium = moles of helium * molar mass of helium
Mass of helium = 0.2595 moles * 4 g/mol
Mass of helium = 1.038 grams
The gas mixture contains 1.038 grams of helium
