Question

The reaction of nh3 and o2 forms no and water. the no can be used to convert p4 to p4o6, forming n2 in the process. the p4o6 can be treated with water to form h3po3, which forms ph3 and h3po4 when heated. part a find the mass of ph3 that forms from the reaction of 1.10 g nh3.

Answer 1

The series of reactions is:

4 NH3 + 5 O2 → 4 NO + 6 H2O 
6 NO + P4 → P4O6 + 3 N2 
P4O6 + 6 H2O → 4 H3PO3 
4 H3PO3 → PH3 + 3 H3PO4 

We multiply the first equation by a number 3 and all the other equations by number 2, so that we get: 
12 NH3 + 15 O2 → 12 NO + 18 H2O 
12 NO + 2 P4 → 2 P4O6 + 6 N2 
2 P4O6 + 12 H2O → 8 H3PO3 
8 H3PO3 → 2 PH3 + 6 H3PO4 

Then the overall reaction is: 
12 NH3 + ... → 2 PH3 + ... 

So calculating for PH3:
(1.10 g NH3) / (17.0306 g NH3/mol) x (2/12) x (33.9976 g PH3/mol) = 0.366 g PH3