A mixture of two gases, $N_2$ and $O_2,$ have a total pressure of $2\mathrm{.}5$atm. What is the partial pressure of the $O_2$ if there are $5$ moles of $O_2$ and $2\mathrm{.}5$ moles of $N_2$

$0\mathrm{.}50$atm

$1\mathrm{.}7$atm

$2\mathrm{.}0$atm

$5\mathrm{.}0$atm