Final answer:
To calculate the equivalent mass of P2O5, we need the molar relationships and a balanced chemical equation; however, the question lacks this information. The process described for a similar analysis involves finding the concentration (mass percent) of MgSO4.
Step-by-step explanation:
To calculate the equivalent mass of P2O5 initially in the sample when 1.000g of MgNH4PO4x6H2O is obtained, we need to understand the molar relationship between these compounds. The equivalent weight of a compound can be found by dividing its molar mass by the number of equivalents per mole. For P2O5, each mole contains 2 equivalents of phosphorus. However, the question does not provide sufficient information to determine the percentage of P2O5. Notably, a gravimetric analysis procedure is highlighted for a different compound (MgSO4) where the concentration (mass percent) of MgSO4 is determined through precipitation with Ba(NO3)2 to form BaSO4.