Final answer:
To balance the given chemical equation, X is 4, Y is 5, and Z is 2, corresponding to the equation 4 P + 5 O2 ➡ 2 P2O5, which makes option A (X=4, Y=5, Z=2) the correct one.
Step-by-step explanation:
To balance the equation X P (s) + Y O₂ (g) ➡ Z P₂O₅ (s), we must find the values of X, Y, and Z that ensure the same number of each type of atom appears on both sides of the equation. The product P₂O₅ contains 2 phosphorus atoms and 5 oxygen atoms. Therefore, a coefficient of 4 for P would give us a total of 4 phosphorus atoms, requiring us to place a coefficient of 2 in front of P₂O₅ to balance the phosphorus atoms.
To balance oxygen, since we now have 2 times 5 oxygen atoms in the product, which gives us 10 oxygen atoms, we need 5 O₂ molecules to provide those 10 oxygen atoms, as each O₂ molecule contains 2 oxygen atoms. Hence, the coefficient Y equals 5
The correctly balanced equation is 4 P (s) + 5 O₂ (g) ➡ 2 P₂O₅ (s), so the correct coefficients are X=4, Y=5, Z=2. Therefore, option A is the correct answer.