Answer:
calcium phosphate has the formula Ca3(PO4)2, which has the mass of 310 grams/mol.
1 mol contains 310 grams
2.3*10^-4 moles contain 2.3*10^-4 * 310, which means 713*10^-4 grams, or 71.3 milligrams.
If you wrote the formula right and named the compound wrong, all you have to do is replace 310 with 278 and the answer will be 639.4*10^-4 grams, or 63.94 milligrams.