MgNH4PO4 6H2O loses H2O stepwise as it is heated. Between 40 and 60 degrees celcius the monohydrate is formed, and above 100 degrees celcius the anhydrous material is formed. What are the phosphorus percentages of the monohydrate and of the anhydrous material?

The answer to your question is below

Explanation:

Data

MgNH₄PO₄ 6 H₂O

40-60°C Monohydrate   MgNH₄PO₄ H₂O

above 100°C                   MgNH₄PO₄ H₂O

1.- Calculate the phosphorus percent of the monohydrate

molecular mass = (24 x 1) + (14 x 1) + (6 x 1) + (31 x 1) + (16 x 5)

molecular mass = 24 + 14 + 6 + 31 + 80

                          = 155 g

atomic mass of phosphorus = 31

                         155 g of the monohydrate 100%

                            31g                                     x

                            x = (31 x 100) / 155

                           x = 20 %

2.- Calculate the mass percent of phosphorus of the anhydrous

molecular mass =  (24 x 1) + (14 x 1) + (4 x 1) + (31 x 1) + (16 x 4)

molecular mass = 24 + 14 + 4 + 31 + 64

molecular mass = 137 g

                            137 g 100%

                             31 g   x

                              x = (31 x 100)/137

                              x = 22.6 %