The vapour denisty of a mixture containing NO2 & N2O4 is 38.3 at 27 deg C. Calculate the moles of NO2 in 100 g of mixture.
The vapor density is the mass of a volume of the mixture divided by the mass of an equal volume of H2 at the same P and T. If we take a mole sample, then
(molar mass mixture/2.016) = 38.3
molar mass mixture = 2.016*38.3= ??
Then let f = fraction of NO2 in the mixture and 1-f = fraction of N2O4.
molar mass NO2 = 46
molar mass N2O4 = 92
46(f) + 92(1-f) = 2.016*38.3
Solve for f.
then f x 100 = grams NO2.
Nearly 0.437
.437
To calculate the moles of NO2 in 100 g of mixture, follow these steps:
1. Calculate the molar mass of the mixture using the given vapor density of 38.3. The vapor density is the ratio of the molar mass of the mixture to the molar mass of hydrogen gas (H2) at the same pressure (P) and temperature (T).
(molar mass mixture / molar mass of H2) = vapor density
molar mass mixture = vapor density * molar mass of H2
molar mass of H2 = 2.016 g/mol (from periodic table)
molar mass mixture = 38.3 * 2.016 = 77.1168 g/mol
2. Let's assume the fraction of NO2 in the mixture is 'f'. The fraction of N2O4 in the mixture is then '1-f'.
3. Calculate the molar mass of NO2 and N2O4. The molar mass of NO2 is 46 g/mol, and the molar mass of N2O4 is 92 g/mol.
4. Use the equation:
(molar mass of NO2 * f) + (molar mass of N2O4 * (1-f)) = molar mass mixture
(46f) + (92(1-f)) = 77.1168
5. Solve the equation to find the value of 'f'. This will give you the fraction of NO2 in the mixture.
6. Once you have the value of 'f', you can calculate the grams of NO2 in 100 g of mixture by multiplying 'f' by 100 g.
Note: Ensure that the temperature is in Kelvin (27°C = 27 + 273 = 300 K) for accurate calculations.