Question

How many boron atoms are there in 2.00 g of boron?

Answer 1

Hi ,

Atomic weight of boron = 10.8 g/mole

given weight = 2.00g

we know that ,

Number of atoms = Number of moles × Avogadro's constant

Number of moles = given weight / atomic weight 

                             = 2 / 10.8 mol

Now , 

Number of atom's = 2 / 10.8 ×Avogadro's constant  

{ Avogadro's constant = 6.023 ×10^23 }

Number of atoms = 2 / 10.8 × 6.023 ×10^23

                             = 12.046 × 10^23 / 10.8

                             = 1.115 × 10 ^23

Hence number of atoms in 2.00g of boron = 1.115 × 10^23

I hope this helps you.

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