Question

Calculate the number of atoms in 507 μg of scandium. Enter your answer in scientific notation.

Answer 1

given

mass of Sc = 507x10^-6 g
molar mass of Sc=44.96 g/mol

number of moles of Sc present in 507x10^-6 g of Sc
= 507x10^-6 g/44.96 g/mol
= 11.2766 x10^-6 mols
According to mol concept
1 mol atoms/molecule contain 6.022 x10^23 atoms/molecules

therefore

11.2766 x10^-6 mols Sc contain 11.2766 x10^-6 mols * 6.022 x10^23 atoms
= 67.91 x10^17 atoms

Answer : number of atoms of Sc= 6.791 x10^18 atoms
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