Question

1.68 g iron contains how many moles of iron? Calculate, the number of atoms in same amount of iron. (At. mass of Fe = 56).

Answer 1

Number of moles = mass of substance/mass of one mole
= \(\frac{1.68}{56}\) = 0.03 moles
1 mole of iron contains 6.023 × 10²³ atoms
0.03 moles of iron will contain 0.03 x 6.023 × 10²³  atoms
= 1.8 ×10²²  atoms