A mixture containing 235 mg of Helium and 325 mg of neon has a total pressure of 453 torr. What is the partial pressure of Helium
To find the partial pressure of helium, we need to use Dalton's law of partial pressures. According to this law, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the individual gases.
First, we need to calculate the mole fraction of helium in the mixture. The mole fraction (X) of a gas is the ratio of the number of moles of that gas to the total number of moles of all the gases present.
To calculate the mole fraction of helium, we need to find the number of moles of each gas present in the mixture. We can use the formula:
Number of moles = mass / molar mass
The molar mass of helium (He) is approximately 4.0 g/mol, and the molar mass of neon (Ne) is approximately 20.2 g/mol.
Number of moles of helium = 0.235 mg / 4.0 g/mol = 0.05875 mmol
Number of moles of neon = 0.325 mg / 20.2 g/mol = 0.01608 mmol
Next, we can calculate the total number of moles of both gases:
Total number of moles = number of moles of helium + number of moles of neon
Total number of moles = 0.05875 mmol + 0.01608 mmol = 0.07483 mmol
Now, we can calculate the mole fraction of helium:
Mole fraction of helium = number of moles of helium / total number of moles
Mole fraction of helium = 0.05875 mmol / 0.07483 mmol = 0.7849
According to Dalton's law of partial pressures, the mole fraction of a gas is equal to the ratio of its partial pressure to the total pressure. Therefore, we can write:
Mole fraction of helium = partial pressure of helium / total pressure
Rearranging the equation, we can solve for the partial pressure of helium:
Partial pressure of helium = Mole fraction of helium x Total pressure
Partial pressure of helium = 0.7849 x 453 torr
Partial pressure of helium = 356.98 torr
Therefore, the partial pressure of helium in the mixture is approximately 356.98 torr.
moles He = grams/molar mass
moles Ne = grams/molar mass
mole fraction He, XHe = moles He/total moles.
PHe = XHe*453
PNe = XNe*453