A gas cylinder of volume 5.00 L contains 1.00 g of Ar and 0.500 g of Ne. The temperature is 275 K. Find the partial pressure of Ne.
Remember Dalton's Law. The partial pressure of a gas is the pressure it would exhibit in a container independent of any other gas present. So ignore the Ar present.
Use PV = nRT
V = 5.00L
P = solve
n = 0.5g/atomic mass Ne
R = you know.
T = given
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To find the partial pressure of Ne, we can use the ideal gas law equation:
PV = nRT
Where:
P = pressure
V = volume
n = number of moles
R = ideal gas constant
T = temperature
First, we need to calculate the number of moles of Ne present in the gas cylinder. To do this, we can use the equation:
n = m/M
Where:
m = mass of Ne
M = molar mass of Ne
The molar mass of Ne is approximately 20.18 g/mol.
m Ne = 0.500 g
M Ne = 20.18 g/mol
n Ne = 0.500 g / 20.18 g/mol
Next, we need to calculate the total number of moles in the gas cylinder. We can sum the number of moles of Ar and Ne:
n total = n Ar + n Ne
Since 1 mole of any gas occupies 22.4 L at standard temperature and pressure (STP), we can calculate the total number of moles using the equation:
n total = V / V m
Where:
V m = molar volume at STP = 22.4 L/mol
V = 5.00 L
n total = 5.00 L / 22.4 L/mol
Once we have the total number of moles, we can calculate the partial pressure of Ne using the ideal gas law equation:
P Ne = (n Ne / n total) × P total
Where:
P Ne = partial pressure of Ne
n Ne = number of moles of Ne
n total = total number of moles
P total = total pressure
Since the temperature is given in Kelvin, we can now plug in the values and solve for P Ne:
P Ne = (n Ne / n total) × P total
= (0.500 g / 20.18 g/mol) / (5.00 L / 22.4 L/mol) × P total
≈ 0.0312 × P total
Therefore, the partial pressure of Ne is approximately 0.0312 times the total pressure.