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What is the number of atoms in 5g Pb ?  

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econominty | Student, Undergraduate | Honors

Posted May 19, 2013 at 3:05 PM via web

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What is the number of atoms in 5g Pb ?

 

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sciencesolve | Teacher | (Level 3) Educator Emeritus

Posted May 19, 2013 at 3:42 PM (Answer #1)

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You need to evaluate the number of atoms in 5g of lead, hence, you need to determine the number of moles, such that:

`m_(Pb) = Pb(g)*1 (m_(Pb))/(Pb(g))`

`m_(Pb) = 5/207.2 => m_(Pb) = 0.024`

You need to perform the conversion from moles to number of atoms, using Avogadro's number,`6.023*10^23` , such that:

atoms of `Pb = m_(Pb)*6.023*10^23`

atoms of `Pb = 0.024*6.023*10^23`

atoms of `Pb = 1.44*10^22`

Hence, evaluating the number of atoms in 5g Pb yields atoms of `Pb = 1.44*10^22` .

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