Ответ:

а)

N(Fe) = N(Na)

b)

N(Fe) = m / M * N(A) * 1= 1/56 * 6.02*10^23 * 1 = 0.1 at

N(Na) = m/M * N(A)*1 = 1/23*6.02*10^23*1 = 0.26 at

N(Fe) < N(Na)

c)

N(Cu) = m/M * N(A)*1 = 64 / 64 *6.02*10^23*1 = 6.02*10^23 атомов

N(O2) = n(O2)*N(A) = 0.5*6.02*10^23 = 3.01*10^23 атомов

N(Cu) > N(O2)