Well it matters If it touch with liquid or soild, if touched with liquid it is not call wet, but with soild yes because something dry will get went when touched with water but something wet will stay wet when touched with water.
2 and a half
250 x 2 =500
250/2=125
and 125 is a half of 250
so your answer is
2 and a half
C4h10+6.5o2=4co2+5h2o
moles of butane=1.92/58=0.0331 moles
moles of water=0.1655 moles\
as the butane and water has 1 is to 5 molar ratio
0.1655=mass/18
mass=2.98 g
mass of water produced = 2.98 g