Use the molar mass of ammonia to change the grams to moles and then use mole-mole ratio
100. g NH3 (1 mol NH3/ 17.04 g) (3 mol H2/ 2 mol NH)= 8.80 moles H2
B, the opposing forces are the same, thus, the ball doesn't move back or forward.
(H+)(OH-) = Kw
kw= 1 x10^-14
OH-= 1 x10 ^-11
(H+)= KW / OH-
concentration of H+ = (1x10^-14) /.(1 x 10 ^-11) = 1 x10 ^-3
Ph= -log (H+)
PH=-log ( 1 x 10 ^-3) = 3 therefore the solution is acidic since the PH less than 7