Question

A neon-dioxygen mixture contains 70.6 g dioxygen and 167.5g neon. If pressure of the mixture of gases in the cylinder is 25 bar. What is the partial pressure of dioxygen and neon in the mixture ?

Answer 1

Weight of dioxygen $({ O }_{ 2 })$ = 70.6 g

Molar mass of dioxygen = 32 g/mol

$Number\quad of\quad moles\quad of\quad dioxygen\quad =\quad \frac { 70.6 }{ 32\quad g/mol } \quad =\quad 2.21\quad mol$

Weight of Neon = 167.5 g

Molar mass of Neon = 20 g/mol

$Number\quad of\quad moles\quad of\quad neon\quad =\quad \frac { 167.5\quad g }{ 20\quad g/mol } \quad =\quad 8.375\quad mol$

$Mole\quad fraction\quad of\quad dioxygen\quad =\quad \frac { 2.21 }{ 2.21\quad +\quad 8.375 } \\ =\quad \frac { 2.21 }{ 10.585 } \quad \\\\ Mole\quad fraction\quad of\quad dioxygen\quad =\quad 0.21\quad \\ \\Mole\quad fraction\quad of\quad neon\quad =\quad \frac { 8.375 }{ 2.21\quad +\quad 8.375 } \\ \\=\quad \frac { 8.375 }{ 10.585 } \quad \\\\ Mole\quad fraction\quad of\quad neon\quad =\quad 0.79$

We know,

$Partial\quad pressure\quad of\quad a\quad gas\quad (dioxygen)\quad=\quad Mole\quad fraction\quad \times \quad Total\quad pressure\\ \\=\quad 0.21\quad \times \quad 25\quad bar\quad =\quad 5.25\quad bar\quad \\\\ Partial\quad pressure\quad of\quad a\quad gas\quad (neon)\quad \quad =\quad Mole\quad fraction\quad \times \quad Total\quad pressure\\ \\=\quad 0.79\quad \times \quad 25\quad bar\quad =\quad 19.75\quad bar$