Question

Calculate the mass of 1.23×1024 helium atoms.

Answer 1

6.023*1023 He atoms=1 mole He

1.23×1024 helium atoms=1.23×1024/6.023*1023 =2.042 mole He

one mole He=4.0 gm

2.042 mole He=2.042*4.0=8.168 gm

answer in grams of Helium is 8.168 gm