1) Given that 4NH3 + 5O2 ? 4NO + 6H2O, if __4

1) Given that 4NH3 + 5O2 ? 4NO + 6H2O, if __4.26x10^23__________ molecules NH3 were made to react with an excess of oxygen gas, how many molecules of NO would form? 

2) If _25.0_____ moles of sulfur react with ___40.0_____ moles of chlorine, how many moles of disulfur dichloride are produced?  Which reactant is the limiting reactant and which is the reactant in excess? 

S8(l) + 4Cl2(g) ? 4S2Cl2(l)

3. Urea (CH4N2O), can be synthesized by the reaction of ammonia (NH3) with carbon dioxide (CO2): 

2NH3(aq) + CO2(aq) ? CH4N2O(aq) + H2O(l) 

An industrial synthesis of urea obtains 87.5 kg of urea upon reaction of 68.2 kg of ammonia with excess carbon dioxide. Determine the theoretical yield of urea and percent yield for the reaction.