Hi, sry again -_- but i have yet another question.. what am i doing wrong!?

im trying to convert Atoms to Grams. EXample

1.0×1023

so im doing

(1.0×1023

)(1/6.022x10^23)(196.

96655)=3.3g (putting it to 2 sig figs.)

same thing for 2.80×1022

im doing (2.80×1022

)(1/6.022x10^23)(4.002602)=1.9

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last but not least can you guys help me get an idea of how to do this problem i think i know how but want to verify.

How many helium atoms are there in a helium blimp containing 535

of helium?

so i would start off by puting 535 into grams (535000g)then divide by molar mass then multiply by avogadro = atoms (8.0*10^28)