1.) A convenient method of determining the volume of a container of irregular shape is to fill it with a liquid of known density and measure the mass. An empty Erlenmeyer flask marked "10 mL" weighs 26.3251 g. When filled with mercury, with density = 13.5340 g/mL (at 25.0 C), it weighs 176.2510 g.
a.) Calculate the true volume of the flask.
b.) The flask is considered "empty," but it in fact contains air, which has a density = 0.0012250 g/mL. When it contains a gas at 100.0 C, its mass is 26.3415 g. Calculate the molar mass of the gas.
c.) Elemental analysis of the gas shows that it is composed of 85.63 % C, 14.37 % H, and no other elements. What is the molecular formula of the gas?
I'm stuck on a.) and I can't continue to the next part. Any help is appreciated!
I don't think the answer to a is used in the other questions.
mass Hg + flask = 176.2510 g.
mass empty flask = -26.3251
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mass Hg 176.2510-26.3251 = ?
volume = mass/density = substitute and solve for volume
For the true volume of the flask I got 11.0777 mL.
For part b.) I am trying to use the formula:
molar mass = mRT/PV, however I don't know what number to substitute for V.
To calculate the true volume of the flask, you can use the principle of buoyancy. The formula for calculating buoyancy is:
Buoyant force = weight of the liquid displaced = density of the liquid * volume of the liquid displaced * gravitational acceleration
In this case, the liquid being displaced is mercury. Given the density of mercury, which is 13.5340 g/mL, and the weight of the filled flask, which is 176.2510 g, we can calculate the volume of the liquid displaced using the formula:
Volume of the liquid displaced = weight of the liquid displaced / (density of the liquid * gravitational acceleration)
First, convert the density of mercury to g/cm³:
13.5340 g/mL = 13.5340 g/cm³
Next, convert the weight of the liquid displaced to grams:
176.2510 g - 26.3251 g = 149.9259 g
Then, substitute these values into the formula:
Volume of the liquid displaced = 149.9259 g / (13.5340 g/cm³ * 9.81 m/s²)
Convert the units of gravitational acceleration to cm/s²:
9.81 m/s² = 981 cm/s²
Substitute the values and calculate:
Volume of the liquid displaced = 149.9259 g / (13.5340 g/cm³ * 981 cm/s²)
Now, divide the weight by the product of density and gravitational acceleration to find the volume:
Volume of the liquid displaced = 0.0108 cm³
Therefore, the true volume of the flask is approximately 0.0108 cm³.