Determine the volume (in L) of 8.00 g of He gas at 25.0 °C and 770. mmHg. Be sure your answer has the correct number of significant figures.
Note: Reference the Fundamental constants and Conversion factors for non-SI units table for additional information.
L
To determine the volume of the gas, we can use the ideal gas law equation:
PV = nRT
where:
P = pressure = 770. mmHg = 770. / 760 atm = 1.013 atm
V = volume
n = number of moles
R = gas constant = 0.0821 L.atm/(mol.K)
T = temperature = 25.0 + 273 = 298 K
First, we need to calculate the number of moles of He gas using its molar mass:
molar mass of He = 4.00 g/mol
number of moles = mass / molar mass = 8.00 g / 4.00 g/mol = 2.00 mol
Now we can substitute the values into the ideal gas law equation:
(1.013 atm)V = 2.00 mol * 0.0821 L.atm/(mol.K) * 298 K
V = (2.00 * 0.0821 * 298) / 1.013
V = 49.86 L
Therefore, the volume of 8.00 g of He gas at 25.0 °C and 770. mmHg is 49.86 L. This answer has 4 significant figures.