Given 2.0 moles of Barium Phophate, Ba3(PO4)2, how many moles of phosphorous (P) are present?
The correct answer and explanation is:
Correct Answer: 4.0 moles of phosphorus (P)
Explanation:
To find the number of moles of phosphorus in 2.0 moles of barium phosphate, it is important to start by analyzing the chemical formula: Ba₃(PO₄)₂.
This compound is made of three barium (Ba²⁺) ions and two phosphate (PO₄³⁻) ions. Each phosphate ion contains one atom of phosphorus (P).
So, in one formula unit of Ba₃(PO₄)₂, there are:
- 2 phosphate ions × 1 phosphorus atom per phosphate = 2 phosphorus atoms
This means:
- 1 mole of Ba₃(PO₄)₂ contains 2 moles of phosphorus atoms
Now, if the sample contains 2.0 moles of Ba₃(PO₄)₂, the number of moles of phosphorus is:
- 2.0 moles of Ba₃(PO₄)₂ × 2 moles of P / 1 mole of Ba₃(PO₄)₂ = 4.0 moles of phosphorus atoms
This calculation uses the concept of mole ratios, which helps in converting between the amount of a compound and the amount of specific elements within it.
Understanding mole ratios is key to interpreting chemical formulas. The subscripts in the formula (like the 3 in Ba₃ and 2 in (PO₄)₂) show how many atoms or groups are in each molecule or formula unit. In Ba₃(PO₄)₂, the 2 after the phosphate group means there are two phosphate ions, and each phosphate contains one phosphorus atom. That leads to a total of two phosphorus atoms per unit.
Therefore, with 2.0 moles of barium phosphate, there are 4.0 moles of phosphorus atoms present.