Determine the proportion of nitrogen in a mixture of nitrogen and hydrogen having a hydrogen density of 4.25.

First, we find the molar mass of the mixture by multiplying the density for hydrogen by its molar mass:
M (cm) = D * M (H2) = 4.25 * 2 = 8.5 g / mol.
Next, you need to use the formula:
w (N2) * M (N2) + w (H2) * M (H2) = M (cm), where w is the volume fraction of the corresponding component in the mixture, M is the molar mass of each component in the mixture and M (cm) is the molar weight see
In addition, it is known: w (N2) + w (H2) = 1, so we compose the equation:
w (N2) * 28 + w (H2) * 2 = 8.5
w (N2) * 28 + (1 – w (N2)) * 2 = 8.5
w (N2) = 0.25.