Question

Determine the number of atoms in each sample.

a. 10.0 g Sr

b. 10.0 g Mg

c. 28.5 kg Zn

Answer 1

a) Atomic mass of Strontium atom = 87.62 gm/mol

1 mole contains 6.023 * 10^(23) atoms

Hence number of atoms in 10g of Sr will be

=> 10/87.62 * 6.023 * 10^(23) atoms

=> 6.874 * 10^(22) atoms

b) Atomic mass of Magnesium atom = 24.31 gm/mol

1 mole contains 6.023 * 10^(23) atoms

Hence number of atoms in 10g of Mg will be

=> 10/24.31 * 6.023 * 10^(23) atoms

=> 2.477 * 10^(23) atoms

c) Atomic mass of Zinc = 65.38 gm/mol

1 mole contains 6.023 * 10^(23) atoms

Hence number of atoms in 28500g of Zn will be

=> 28500/65.38 * 6.023 * 10^(23) atoms

=> 2.625 * 10^(26) atoms