A mixture of 8.00 g He and 26.5 g Ne has a pressure of 820. mm Hg. What is the partial pressure of each of the gases?
Convert g He and g Ne to moles. moles = grams/molar mass.
Then use PV = nRT and solve for P for each gas.
To find the partial pressure of each gas in a mixture, we can use Dalton's Law of Partial Pressures.
According to Dalton's Law, the total pressure of a mixture of ideal gases is equal to the sum of the partial pressures of each individual gas.
In this case, we have a mixture of helium (He) and neon (Ne), and we want to find the partial pressure of each gas.
Step 1: Calculate the moles of each gas.
To find the moles of each gas, we need to divide the given mass of each gas by their respective molar masses.
The molar mass of helium (He) is 4.00 g/mol, so the number of moles of helium can be calculated as:
Moles of He = Mass of He / Molar mass of He
= 8.00 g / 4.00 g/mol
= 2.00 mol He
The molar mass of neon (Ne) is 20.18 g/mol, so the number of moles of neon can be calculated as:
Moles of Ne = Mass of Ne / Molar mass of Ne
= 26.5 g / 20.18 g/mol
= 1.31 mol Ne
Step 2: Calculate the partial pressure of each gas.
To find the partial pressure of each gas, we can use the formula:
Partial pressure = Mole fraction × Total pressure
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 gases in the mixture.
Mole fraction of He (X_He) = Moles of He / Total moles
= 2.00 mol He / (2.00 mol He + 1.31 mol Ne)
= 0.605
Mole fraction of Ne (X_Ne) = Moles of Ne / Total moles
= 1.31 mol Ne / (2.00 mol He + 1.31 mol Ne)
= 0.395
Now, we can calculate the partial pressure of each gas using the mole fractions and the given total pressure.
Partial pressure of He = X_He × Total pressure
= 0.605 × 820. mm Hg
= 496.1 mm Hg (rounded to the nearest tenth)
Partial pressure of Ne = X_Ne × Total pressure
= 0.395 × 820. mm Hg
= 323.9 mm Hg (rounded to the nearest tenth)
Therefore, the partial pressure of helium (He) is approximately 496.1 mm Hg, and the partial pressure of neon (Ne) is approximately 323.9 mm Hg.