What is the formula for copper(II) phosphate? Capitalization and punctuation count. How many atoms of phosphorus are in 6.20 mol of copper(II) phosphate?

Answer 1

Copper(II) tells us that we have Cu²⁺

Phosphate = PO₄^3-

To put these together and have a neutral compound (no net charge), we need 3 of the Cu²⁺ and 2 of the PO₄^3- so that the charges neutralize each other. Thus, the formula for copper(II) phosphate is...

Cu₃(PO₄)₂

To find the number of atoms of phosphorous (P) in 6.20 mol of copper(II) phosphate, we use Avogadro's number (6.02x10²³ atoms/mol) and the fact that each mol of copper(II) phosphate contains mols of P (phosphorous). Look at the formula for copper(II) phosphate above and not that the sub 2 outside the parentheses applies to both the P and the O, so there are 2 P's and 8 O's in each unit of the molecule.

So, atoms of P would be calculated as follows:

6.20 mol Cu₃(PO₄)₂ x 6.02x10²³ atoms Cu₃(PO₄)₂ / mol x 2 mol P / mol Cu₃(PO₄)₂ = 7.46x10²⁴ atoms of P