Consider three one-liter flasks labeled A, B, and C filled with the gases NO, NO2, and N2O, respectively, each at STP.
Which flask contains 1.0 mole of gas?
All are the same
To determine which flask contains 1.0 mole of gas, we need to compare the molar masses of the gases NO, NO2, and N2O.
The molar mass of NO (nitric oxide) is 30.01 g/mol.
The molar mass of NO2 (nitrogen dioxide) is 46.01 g/mol.
The molar mass of N2O (nitrous oxide) is 44.02 g/mol.
Since we have 1.0 mole of gas, we need to find the gas with a molar mass closest to 1.0 mole.
Comparing the molar masses, we can see that NO has the closest molar mass to 1.0 mole (30.01 g/mol).
Therefore, flask A, which contains NO, contains 1.0 mole of gas.
To determine which flask contains 1.0 mole of gas, we need to compare the number of moles of each gas in each flask. The ideal gas law can be used to calculate the number of moles of a gas given its volume, pressure, and temperature.
However, in this case, we are told that the flasks contain gases at STP (Standard Temperature and Pressure). At STP, the pressure is 1 atmosphere (atm) and the temperature is 0 degrees Celsius (273.15 Kelvin or K).
Since the volume of each flask is 1 liter, we can assume that their volumes are the same.
Now, let's calculate the moles of each gas in each flask:
Flask A (labeled NO): Since we have 1.0 mole of gas in question, we can assume that Flask A contains 1.0 mole of NO.
Flask B (labeled NO2): At STP, 1 mole of any gas occupies a volume of 22.4 liters. Since the volume of Flask B is 1 liter, it can contain 1/22.4 moles of NO2.
Flask C (labeled N2O): Similarly, at STP, 1 mole of any gas occupies a volume of 22.4 liters. Since the volume of Flask C is 1 liter, it can contain 1/22.4 moles of N2O.
Comparing the results:
- Flask A contains 1.0 mole of NO.
- Flask B contains 1/22.4 moles of NO2.
- Flask C contains 1/22.4 moles of N2O.
Therefore, Flask A contains 1.0 mole of gas, which is the desired answer.
PV = nRT and
n = PV/RT
Plug in P, V, R, and T and you can calculate n.