Final answer:
To find the number of moles in 250.0 g of Ca(H2PO4)2, calculate its molar mass and divide the mass of the sample by the molar mass. The result is 1.068 moles of Ca(H2PO4)2 in the given sample.
Step-by-step explanation:
First, we need to calculate the molar mass of Ca(H2PO4)2 to determine how many moles are in 250.0 g of the compound. Calcium (Ca) has an atomic mass of approximately 40.08 u, hydrogen (H) 1.01 u, phosphorus (P) 30.97 u, and oxygen (O) 16.00 u. The molar mass of Ca(H2PO4)2 can be calculated as follows:
Molar mass = 1(Ca) + 2(2H) + 2(1P) + 2(4O) = 1(40.08) + 2(2*1.01) + 2(30.97) + 2(4*16.00) = 40.08 + 4.04 + 61.94 + 128.00 = 234.06 g/mol
Now that we have the molar mass, we can determine the number of moles in 250.0 g of Ca(H2PO4)2:
Moles = mass / molar mass = 250.0 g / 234.06 g/mol = 1.068 moles
Therefore, there are 1.068 moles of Ca(H2PO4)2 in 250.0 g of the compound.