Consider the following balanced reaction: cu + 4hno3 →→ cu(no3)2 + 2no2 + 2 h2o if 0.0424 mol cu are mixed with 0.160 mol hno3 , how many moles of h2o form?

The answer 
the equation of reaction is
 
Cu     +                4HNO3     →→     Cu(NO3)2     +     2NO2     +     2 H2O
1mole                  4 moles                  1mole                  2 moles       2 moles 

0.0424 mol > 0.160 mol                                                               moles

we can find it by applying mole ration formula, 

1/0.0424  =2/ n H2O  or 4/0.16= 2/nH2O

nH2O is the number of mole that has been formed

so 1x nH2O =2 x 0.0424=>    nH2O= 0.0848 moles
or  4x nH2O= 2x0.16=>   nH2O= 0.08 moles

so the answer is 0.0848 moles