Question

Ammonium phosphate ((NH 4) 3 PO 4) is an important ingredient in many fertilizers. It can be made by reacting phosphoric acid H 3 PO 4 with ammonia NH 3 . What mass of ammonium phosphate is produced by the reaction of 9.37 g of ammonia? Round your answer to 3 significant digits.

Answer 1

molar mass of NH3 = 17 g/mol
number of mol of NH3 = (given mass)/(molar mass)
= 9.37/17
= 0.551 mol

reaction taking place
H3PO4 + 3NH3 --> (NH4)3PO4
according to reaction
3 mol of NH3 give 1 mol of (NH4)3PO4
1 mol of NH3 give 1/3 mol of (NH4)3PO4
0.551 mol of NH3 give (1/3)*0.551 mol of (NH4)3PO4
0.551 mol of NH3 give 0.184 mol of (NH4)3PO4
so,
number of mol of (NH4)3PO4 formed = 0.184 mol

molar mass of (NH4)3PO4 = 149 g/mol
mass of (NH4)3PO4 = (number of mol of (NH4)3PO4 formed)*(molar mass of (NH4)3PO4 )
= 0.184*149
= 27.4 g

Answer: 27.4 g