A 200.0 mL flask contains 1.03 mg of O2 and 0.41 mg HE at 288K. Calculate the partial pressure of oxygen and helium in the flask. What is the total pressure?
I would convert mg O2 to moles (moles = grams/molar mass) and use PV = nRT to solve for pressure. Do the same for He. Add the partial pressures to find the total P.
@DrBob222
thanks once again for your generous help :)
To calculate the partial pressure of oxygen and helium in the flask, you can use the Ideal Gas Law equation:
PV = nRT
where:
P is the pressure
V is the volume
n is the amount of gas
R is the ideal gas constant
T is the temperature
First, let's convert the mass of oxygen and helium to moles:
1. Convert mass of oxygen to moles:
moles of O2 = mass of O2 / molar mass of O2
The molar mass of O2 is 32.00 g/mol.
So, moles of O2 = 1.03 mg / (32.00 g/mol) / (1000 mg/g) = 3.22 x 10^-5 mol
2. Convert mass of helium to moles:
moles of He = mass of He / molar mass of He
The molar mass of He is 4.00 g/mol.
So, moles of He = 0.41 mg / (4.00 g/mol) / (1000 mg/g) = 1.03 x 10^-4 mol
Now, let's calculate the partial pressure of oxygen and helium:
Partial pressure of oxygen = moles of O2 * R * T / V
Using:
R = 0.0821 L·atm/(mol·K)
T = 288 K
V = 200.0 mL = 0.200 L
Partial pressure of oxygen = (3.22 x 10^-5 mol) * (0.0821 L·atm/(mol·K)) * (288 K) / (0.200 L)
= 0.119 atm (rounded to three decimal places)
Similarly, the partial pressure of helium can be calculated as:
Partial pressure of helium = moles of He * R * T / V
Partial pressure of helium = (1.03 x 10^-4 mol) * (0.0821 L·atm/(mol·K)) * (288 K) / (0.200 L)
= 0.293 atm (rounded to three decimal places)
Finally, we can calculate the total pressure by summing up the partial pressures:
Total pressure = Partial pressure of oxygen + Partial pressure of helium
= 0.119 atm + 0.293 atm
= 0.412 atm (rounded to three decimal places)
Therefore, the partial pressure of oxygen is 0.119 atm, the partial pressure of helium is 0.293 atm, and the total pressure is 0.412 atm.
To calculate the partial pressure of a gas in the flask, we need to use the ideal gas law equation:
PV = nRT
Where:
P is the pressure of the gas
V is the volume of the flask
n is the number of moles of the gas
R is the ideal gas constant
T is the temperature in Kelvin
First, let's calculate the number of moles of oxygen and helium in the flask.
To calculate the number of moles, we use the formula:
moles = mass / molar mass
The molar mass of oxygen (O2) is 32 g/mol, and the molar mass of helium (He) is 4 g/mol.
1. Convert the mass of oxygen to grams:
1.03 mg = 0.00103 g
2. Calculate the number of moles of oxygen:
moles of O2 = 0.00103 g / 32 g/mol
3. Convert the mass of helium to grams:
0.41 mg = 0.00041 g
4. Calculate the number of moles of helium:
moles of He = 0.00041 g / 4 g/mol
Now that we have the number of moles of oxygen and helium, we can calculate the partial pressure of each gas using the ideal gas law.
1. Calculate the partial pressure of oxygen (PO2):
PO2 = (moles of O2 * R * T) / V
2. Calculate the partial pressure of helium (PHe):
PHe = (moles of He * R * T) / V
The ideal gas constant, R, is 0.0821 L·atm/(K·mol).
Finally, to calculate the total pressure in the flask, we need to sum up the partial pressures of oxygen and helium.
Total pressure = PO2 + PHe
Substitute the given values into the equations, and solve for each quantity to find the partial pressures and the total pressure.