The average atomic mass of your mixture is 1.03 u
.
The average atomic mass of H is the weighted average of the atomic masses of its isotopes.
We multiply the atomic mass of each isotope by a number representing its relative importance (i.e., its % abundance).
Thus,
0.99 × 1.01 u = 0.998 u
0.002 × 2.01 u = 0.004 u
0.008 × 3.02 u = <u>0.024 u</u>
TOTAL = 1.03 u
<h3>The density of H₂ = 0.033 g/L</h3><h3>Further explanation</h3>
In general, the gas equation can be written

where
P = pressure, atm , N/m²
V = volume, liter
n = number of moles
R = gas constant = 0.082 l.atm / mol K (P= atm, v= liter),or 8,314 J/mol K (P=Pa or N/m², v= m³)
T = temperature, Kelvin
n = N / No
n = mole
No = Avogadro number (6.02.10²³)
n = m / MW
m = mass
MW = molecular weight
For density , can be formulated :

P = 327 mmHg = 0,430263 atm
R = 0.082 L.atm / mol K
T = 48 ºC = 321.15 K
MW of H₂ = 2.015 g/mol
The density :

Answer:
the reactivity of alkaline earth metals increases from top to the bottom of the group, that's because the atoms get bigger from the top to the bottom so the valence electrons are farther from the nucleus.