The pressure gauge on a cylinder used to fill balloons with He shows a pressure of 1275 psi at a temperature of 25.00 $\circ$ C.Assuming the cylinder has a volume of 10.0 L,how many grams of He does the cylinder contain?

Question

Quizplus · Accepted Answer

Using the Ideal Gas Law equation PV=nRT, we can find the number of moles of He in the cylinder:
n = (PV)/(RT)
Convert the temperature to Kelvin:
T = (25.00 + 273.15) K = 298.15 K
Convert the pressure to atmospheres:
P = 1275 psi * 1 atm/14.696 psi = 86.72 atm
Substitute the values into the equation:
n = (86.72 atm * 10.0 L)/(0.08206 L*atm/mol*K * 298.15 K) = 3.516 mol He
Finally, we can convert moles to grams using the molar mass of He:
m = n * M = 3.516 mol * 4.003 g/mol = 14.08 g He
Therefore, the cylinder contains 14.08 grams of He, which is closest to choice B (142 g).

The Pressure Gauge on a Cylinder Used to Fill Balloons ∘\circ∘

The Pressure Gauge on a Cylinder Used to Fill Balloons $\circ$