Answer
$p = 35.5~keV/c$
Work Step by Step
We can find the momentum:
$p = \frac{h}{\lambda}$
$p = \frac{6.63\times 10^{-34}~J~s}{35.0\times 10^{-12}~m}$
$p = 1.894\times 10^{-23}~J~s/m$
$p = (1.894\times 10^{-23}~J~s/m)(\frac{1~eV}{1.6\times 10^{-19}~J})(\frac{3.0\times 10^8~m/s}{c})$
$p = 3.55\times 10^4~eV/c$
$p = 35.5~keV/c$
