Mass of an empty flask and stopper is 55.844g. 5mL of an unknown liquid is added and heated in a water bath at 99.7 degrees C. It then cools down. The stopper is removed and then replaced. The weight of all of this is 56.101g. The volume of the flask is 248.1 mL. Barometric pressure is 752 mm Hg. R=.0821 L atm/(mole K)
How do I find the pressure of the vapor?
What was the mass of the vapor in the flask?
Idk how to go about this..any help at all will be greatly appreciated ^_^
To find the pressure of the vapor, you can use the Ideal Gas Law equation, which is given by:
PV = nRT
Where:
P is the pressure of the vapor
V is the volume of the flask
n is the number of moles of the vapor
R is the ideal gas constant
T is the temperature in Kelvin
First, we need to find the number of moles of the vapor. To do this, we can use the equation:
moles = volume / molar volume
Where:
volume is the volume of the liquid added, which is given as 5 mL
molar volume is the volume occupied by one mole of a gas at a specific temperature and pressure, which is typically given as 22.4 L/mol at standard conditions (0 degrees Celsius and 1 atm)
Now, let's calculate the number of moles:
moles = 5 mL / 22.4 L/mol
Next, we convert the volume of the flask from mL to L:
volume = 248.1 mL / 1000 mL/L
Now, we can substitute the values into the Ideal Gas Law equation:
PV = nRT
P * volume = moles * R * T
Since we are solving for P, rearrange the equation:
P = (moles * R * T) / volume
Substitute the known values:
P = (moles * 0.0821 L atm/(mol K) * T) / volume
Now, calculate the pressure of the vapor by plugging in the values you have:
P = (moles * 0.0821 * 99.7 + 273.15) / volume
Finally, substitute the values for moles and volume and calculate the pressure.
To find the mass of the vapor in the flask, you can use the equation:
mass = total weight - empty flask weight
Substitute the known values:
mass = 56.101g - 55.844g
Now, calculate the mass of the vapor in the flask by subtracting the weight of the empty flask from the total weight.
I hope this helps! Let me know if you have any further questions.
To find the pressure of the vapor, you can use the ideal gas law equation:
PV = nRT
Where:
P = pressure of the vapor (what we want to find)
V = volume of the flask (given as 248.1 mL, but we need to convert it to L by dividing by 1000)
n = number of moles of the vapor (what we want to find)
R = ideal gas constant (given as 0.0821 L atm/(mole K))
T = temperature in Kelvin (we need to convert from Celsius to Kelvin)
First, let's convert the volume from mL to L:
Volume (V) = 248.1 mL / 1000 = 0.2481 L
Next, let's convert the temperature from Celsius to Kelvin:
Temperature in Kelvin (T) = 99.7°C + 273.15 = 372.85 K
Now we can rearrange the ideal gas law equation to solve for the pressure (P):
P = nRT / V
However, we don't have the value for the number of moles of the vapor (n) yet. To find it, we need to use the molar mass of the unknown liquid.
You'll need to know the molar mass of the unknown liquid to calculate the number of moles. Once you have the molar mass, you can calculate the number of moles by dividing the mass of the liquid by the molar mass of the liquid.
Let's assume the molar mass of the liquid is M. Since the mass of the liquid is given as:
Mass of the liquid = 56.101g - 55.844g = 0.257g
Number of moles (n) = Mass of the liquid / M
Now that we have the number of moles, we can substitute it back into the ideal gas law equation to find the pressure (P).
P = (Mass of the liquid / M) * RT / V
To find the mass of the vapor in the flask, we subtract the mass of the empty flask and stopper from the total weight:
Mass of the vapor = Total weight - Mass of the empty flask and stopper
Mass of the vapor = 56.101g - 55.844g
I hope this helps! Let me know if you have any further questions.