Answer
$269\ g$
Work Step by Step
Mass:
$0.791\ g/mL\times 1000\ mL=791\ g$
Percent yield:
$74\%=791\ g/T.Y. \times 100\%$
$T.Y.= 1068.92\ g$
Number of moles of methanol:
$1068.92\ g/16.04\ g/mol=66.64\ mol$
From stoichiometry:
$66.64\ mol\times 2_{H_2}/1_{CH_4}\times 2.016\ g/mol=269\ g$
