Under certain conditions the rate of this reaction is zero order in ammonia with a rate constant of $0\mathrm{.}0054M*s^{-1}$ :

$2N{H}_3(g)N_2(g)+3H_2(g)$

Suppose a $5\mathrm{.}0L$ flask is charged under these conditions with $250.$mmol of ammonia. How much is left $2\mathrm{.}0s$ later? You may assume no other reaction is important.

Be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.