How many moles of h2o are produced when 64.0 g c2h2 burns in oxygen?

the balanced eqaution for the combustion of C2H2 is as follows
2C₂H₂  + 5O₂ --> 4CO₂ + 2H₂O
   
stoichiometry of C₂H₂ to H₂O is 2:2 .
Number of moles of C₂H₂ = mass present / molar mass of C₂H₂  
Since molar mass of C₂H₂  is 26 g/mol.
Number of C₂H₂  moles reacted = 64.0 g / 26 g/mol = 2.46 mol.
according to molar ratio of 2:2.
the number of H₂O moles formed = number of C₂H₂  moles reacted.
Therefore number of H₂O moles produced = 2.46 mol

Velocity=total displacement/timefrom house to store is 500 from store to neighbor is 200 therefore total displacement=500+200=700metrestherefore,700metres/910seconds=0.8metres per second