N=NA*n
n=m/M
M(P2O5) = 141.94 g/mol
n(P2O5) = 0.650 g/141.94g/mol = 0.00458 mol
N(P2O5) = 0.00458 mol * 6.022*1023 mol-1 = 2.76*1021 molecules
1 molecule of P2O5 contains 2+5 = 7 atoms
2.76*1021 molecules of P2O5 contain x atoms
1/2.76*1021 = 7/x
x= 1.93*1022 atoms
Answer: 1.93*1022
Comments
Leave a comment