[jansan]

Hey I am struggling with a whole assignment, but this is only the first problem, all help is appreciated:
2)Which one of the following is not true concerning 2.00 L of 0.100 M solution of Ca3(PO4)2?

A)This solution contains 6.67 × 10^-2 mol of Ca2+.
B)This solution contains 0.200 mol of Ca3(PO4)2.
C)1.00 L of this solution is required to furnish 0.300 mol of Ca2+ ions.
D)This solution contains 0.800 mol of oxygen atoms.
E)There are 6.02 × 1022 phosphorus atoms in 500.0 mL of this solution.

[sjb]

OK, let's break this down a little. What does 2.00 L of 0.100 M solution of Ca₃(PO4)₂ mean?

e.g. how much calcium phosphate is there?
how many calcium ions, how many phosphate ions? ...