Question

Calculate the no.of atom in 80g of calcium.

Answer 1

just replace grams by  daltons :80u

so its atomic mass no is 80u

we have formula: total no. in grams /by total no in dalton

80g/80u=1 atom

Answer 2

Here your answer

Frist calculate no of moles by divide calcium mass over molar mass of calcium n=ms÷Mwt=80÷40=2mol

No of atoms = no of moles × avogadros no

Nu = n× Na= 2×6×10^23=1.2×10^24