Question

Earth has mass of 5.98*1024 kg. The average mass of the atoms that make up the earth is 40u. How many number of atoms are there in earth ????????

Answer 1

1u = 1.66 * 10^-27 kg

Mass of on atom in kg = 40 * 1.66 * 10^-27 kg

Number of atoms in Earth = (5.98 * 10^24) / (40 * 1.66 * 10^-27)
= 9.00 * 10^49 atoms

Answer 2

"The mass of earth is given as 5.98*1024 kg. The average mass is 4u.

It is a known fact that 1u = 1.66 * 10^-27 kg

The mass of atom in kg  is 40 * 1.66 * 10^-27 kg

So, the number of atoms available  in Earth is (5.98 * 10^24) / (40 * 1.66 * 10^-27).

= 9.00 * 10^49 atoms

"