An atom of xenon has a radius 

r

Xe

=108.

pm

and an average speed in the gas phase at25

°C

of137

.⁢/

m

s

.Suppose the speed of a xenon atom at 

25

°C

has been measured to within1.0

%

. Calculate the smallest possible length of box inside of which the atom could be known to be located with certainty.