Question

Question 2
Which has more number of atoms, 100 grams of sodium or 100 grams of iron (given, atomic mass of Na = 23 u, Fe = 56 u)?

Answer 1

Atomic mass of Na = 23 u (given)
Then, gram atomic mass of Na = 23 g
Now, 23 g of Na contains $6.022\times {10}^{23}$ number of atoms.
Thus, 100 g of Na contains: $\frac{6.022\times {10}^{23}}{23\times 100}numberofatoms=2.6182\times {10}^{24}$
Again, atomic mass of Fe = 56 u (given)
Then, gram atomic mass of Fe = 56 g
Now, 56 g of Fe contains $6.022\times {10}^{23}$ number of atoms
Thus, 100 g of Fe contains: $\frac{6.022\times {10}^{23}}{56\times 100}numberofatoms$
$=1.0753\times {10}^{24}$
Therefore, 100 grams of sodium contain more number of atoms than 100 grams of iron.