Is this a question or do you need a legitimate answer of something? If so please "add more details".
According to Avogadro's law 1 mole contains 6.022 ×10^23 particles
1 mole of carbon = 44.01 g/ mol
Therefore;
44.01 g = 6.022 ×10^23 molecules
Hence, 1.68×10^26 molecules will have a mass of ;
(44.01 × 1.68×0^26) / 6.022×10^23
= 1.228 × 10^4 molecules
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
10^8 just makes it easier to write out big numbers. It makes it so you don't have to keep writing out the really long number over and over.
If you were wondering.
3.0 * 10^8=300,000,000.0