Which has more number of atoms, 100 gram of sodium or 100 gram of iron ( given atomic mass of Na= 23 u, Fe=56u)?

Explanation

Given mass (m) of Na atom = 100 g
Molar mass of Na atoms = 23 g
Avogadro.s number `(N_(0)) = 6.023 xx 10^(23)`
Number of particles (atoms)
`= ("Given mass")/("Molar mass") xx "Avogadro.s number"`
`implies N = (m)/(M) xx N_(0)`
`implies N = (100)/(23) xx 6.023 xx 10^(23)`
`implies N = 26.181 xx 10^(23)`
Given mass (m) of Fe atoms = 100 g
Molar mass (M) of Fe atoms = 56 g
Avogadro.s number `(N_(0)) = 6.023 xx 10^(23)`
Number of particles (atoms)
= `("Given mass")/("Molar mass") xx "Avogadro.s number"`
`implies N = (m)/(M) xx N_(0)`
`implies N = (100)/(56) xx 6.023 xx 10^(23)`
`implies N = 10.751 xx 10^(23)`
Hence , 100 g of sodium contains more atoms .