This is part of the Data Analysis questions from a laboratory experiment determi

Question

This is part of the Data Analysis questions from a laboratory experiment determing the equilibrium constant for a gas phase reaction of N2O4 to 2NO2.

Regarding the importance of the ballast bulb in these measurements, the change in the measured mass of the bulb arising from air buoyancy effects is equal to the change in air mass brought about by pressure and temperature changes. Using the ideal gas law for air and a propagation of errors treatment, show that for a mean temperature and pressure of 300 K and 1 atm, respectively, a change in the temperature of 1 degree C and in the pressure of 1 torr together can cause a change in the measured mass of about 1.4 mg. Assume a volume of 250 mL. Comment on whether the buoyancy corrections are important in your experiment.

I guess I'm just not understanding where to start, what it's exacltly asking me to do, and what of my experimental values I may need to use? One I get a little more pre information I think I can figure out how to calculate it, any help would be greatly appreciated.

Explanation / Answer

An object weighed in air appears lighter than its actual mass by an amount equal to the mass of air that it displaces. True mass is the mass measured in vacuum. A standard mass in a balance is also affected by buoyancy, so it weighs less in air than in vacuum. A buoyancy error occurs whenever the density of the object being weighed is not equal to the density of the standard mass.

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