Question

one atom of an element A weights 6.644×10^-23.calculate no.of gram atoms in 80 Kg of it.

Answer 1

$80 \times {10}^{ - 3} \times 6.644 \times {10}^{ - 23 = }$

Answer 2

Hey there!
Mass of 1 atom= 6.644 x 10^ 23x mass of atoms.
1 Gram atom= mass of 1 mole of atoms = 6.023 x 10^23 mass of one atom
= 6.023x 10^23 x 6.623x 10^-23 
= 40.13 gm.
= 0.0004 kg 
So, 
Number of gram atoms in 40 kg = 1000.

Hope it helps u!!