1 molecula de apa contine 2 at de H + 1 at. O (H2O)
A(H) = 1 si Z = 1 , stim ca A = Z + n
=> n(H) = 0
A(O) = 16 si Z = 8, stim ca A = Z + n
=> n(O) = 8
=> 1 molecula de apa contine 8 neutroni, in total
=> 1 mol de apa contine 8x6,022x10la23 neutroni
masa moleculara apa = M(H2O) = 18 g/mol
nr. moli = masa/M = 36/18 = 2 moli apa
=>
1 mol de apa contine 8x6,022x10la23 neutroni
2 moli............................ a
=> a = 2x8x6,022x10la23 = 9,635x10la24 neutroni
