Question

Calculate the pressure of a barometer on an aeroplane which is at an altitude of $10Km$. Assume the pressure to be $101.325Kpa$ at sea level and the mean temperature $243K$. Use the average molar mass of air $(80$% $N_2,20$% $O_2)$.

Answer 1

$M^{-}=0.8\times 0.028+0.2\times 0.032=0.0288$

$ln\frac{101.325}{p}=\frac{0.0288\times 9.8\times 10000}{8.3\times 243}$

$p=25.027kpa$