Question

Calculate the no. Of gram atoms in a sample of lead weighing 100 grams

Answer 1

Explanation:

lead (Pb),molecular weight =207.2 u

given mass =100 grams

No.of moles

= given mass ÷ molecular mass

= 100 /207.2

= 0.482625483

No. of atoms in 100g lead =

no.of moles × avagadro number

= 0.482625483 × 6.022× 10²³

no.of atoms in 1 gram of lead

= 0.482625483 × 6.022× 10²³ ÷100

0.482625483× 6.022×10²¹

= 2.90637066 × 10²¹

= 2.91 × 10¹⁴