Question

13 molecules p₂o₅
atoms
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3.94 mol o₂
atoms

Explanation:

Step1: Calculate atoms in \(P_2O_5\)

Each \(P_2O_5\) molecule has \(2 + 5=7\) atoms.
For 13 molecules, \(13\times7 = 91\) atoms.

Step2: Calculate atoms in \(O_2\)

Use Avogadro's number \(N_A=6.022\times10^{23}\) molecules/mol.
Molecules of \(O_2\): \(n = 3.94\space mol\times6.022\times10^{23}\space molecules/mol=2.372668\times10^{24}\) molecules.
Each \(O_2\) molecule has 2 atoms.
Atoms of \(O_2\): \(2.372668\times10^{24}\times2 = 4.745336\times10^{24}\approx4.75\times10^{24}\) atoms.

Answer:

For \(13\) molecules \(P_2O_5\): \(91\) atoms.
For \(3.94\space mol\space O_2\): \(4.75\times10^{24}\) atoms.