Final answer:
The percent composition of phosphorus in calcium phosphate (Ca3(PO4)2) is 19.968%, calculated using the given molar masses of phosphorus and the compound.
Step-by-step explanation:
The percent composition of an element in a compound is calculated by dividing the total mass of the element in one mole of the compound by the molar mass of the compound and multiplying by 100. For calcium phosphate, with the formula Ca3(PO4)2, we have:
- Mass of 2 P: (2 atoms) × (30.973761 amu/atom) = 61.947522 amu
- Formula mass of Ca3(PO4)2: 310.177 amu
To calculate the percent composition of phosphorus, we use the formula:
Percent composition of P = (Mass of P / Formula mass of Ca3(PO4)2) × 100
Plugging in the values we get:
Percent composition of P = (61.947522 amu / 310.177 amu) × 100
Calculating this gives us:
Percent composition of P = 19.968% (to five significant digits)